Yes, I suppose that's true.  You can theoretically fit more inside the phone.  So, what did they add?  I remember when Apple claimed they added a barometer in the space that it used to take up.  I've never heard clear explanations from any other company, so props to them for at least attempting to justify the decision.  Many have not managed anywhere near that much, citing only stupid things like "it's an industry trend", or even "this is what people want".  But I'll ask again, what did the Note 10 gain because of this that wouldn't have otherwise been possible?  Really, if anyone knows, please comment.  Regardless, you should be thinking about this because it better be something.  Furthermore, it better be something you value more than the headphone jack.  Is it thinner?  Longer battery?  Better or more hardware or other features?  Why isn't Samsung (and all others) stating what it is?  I'm sure we're all familiar with the typical marketing page for any product where truth is subjective and often less than meets the eye.  ie, we know companies look for every possible positive bullet point they can but on a box, so where is it?  Where's the one for what has been traded in?  And in the cases where they do "tell" you, remember to actually think to make sure it's reasonable and not just accept it at face value because there's been more than one instance in the past of companies making up easily disprovable nonsense as a justification (see: water resistance as an excuse for non-removable batteries).

Finally, with all that aside though, does it even save space?  In order to retain the same functionality, you now need one of those splitter dongles.  Overall you're still taking up just as much space, it's just external now and attached by an awkward floppy cable.  Just as non-removable batteries allow them to be marginally larger due to not having to have a separate external casing for the phone and the battery, an integrated solution will always be more efficient.

This is by far the most stupid answer, and hopefully after reading my earlier section you can see why.  It's not even a reason why this is better, it's just an attempt at a excuse for why it's not worse.  Even if it was completely useless, which of course it's not, unless you gain something by removing it (in which case your argument is actually that it saves space), nothing has been made better.

Immediately this also fails the test above and thus doesn't even count as a valid argument, but in case you want more, simply consider that wireless is slower to setup, less reliable, and requires batteries, all of which are downgrades vs just plugging in a wire.  The only pro is that you don't have a wire to snag, but again, this is not mutually exclusive.  You can also use wireless on a phone with a headphone jack.

Again, excuses and compromise.  But beyond that, again, there are issues, perhaps most significantly, you lose the ability to charge and listen at the same time.  Yes, you can buy splitter dongles that allow this, but again, excuses and compromise.  You could do that, or you could just not have the problem in the first place.

It absolutely is not and anyone who thinks this needs to take a look around and rethink the topic.  Obsolete means that it's falling out of favour and being replaced or removed on most devices, and/or that something better has been created.  Neither of these things are true of the headphone jack.

A cursory look through the electronics in your house, or in a store, or really anywhere will reveal that it's actually a very common port on a huge variety of devices.  Whether it's a TV receiver, mixer board, your car stereo, PC motherboard, microphone/headset, or anything else that deals with sound, it probably has this port.  Only smartphones are trying to get rid of it - this trend does not exist anywhere else that I've noticed.

In addition to being very common (which is testament to its good properties), it is simple, robust, compact, and highly compatible.  It is genuinely difficult to imagine a way to improve it, which is impressive for a design that's existed relatively unchanged for over 80 years.  Could it be smaller?  It's already much smaller than USB.  Could it be stronger?  People always talked about breaking Micro B ports, I've never heard of someone snapping a 3.5 mm plug.  Could it be easier to plug in?  We've all seen the USB flipping superposition memes, but the headphone jack is round, you literally cannot get it wrong.  Could it be improved electrically?  It's literally the least possible hardware necessary for delivering sound - just 3 wires that go directly to the driver of your speakers or headphones, possibly through an amp if necessary.  You could transmit the audio data in many other ways but at some point it has to turn into a 2 wire analog signal, and so if it's not already in this form, that means more processing is necessary before it gets there.  You could break the signal chain from device to speaker somewhere in the digital portion rather than in the last analog stage, and this would have certain advantages, mainly that quality could be preserved completely losslessly over any distance but a) I dare you to hear the difference between a 3 ft analog cable and a 12 ft one, and b) this would certainly destroy compatibility.  How many times have you needed a DP to HDMI or DVI or VGA adapter?  How about USB A to USB C, or the other way around?  PS/2 to USB perhaps?  How about two devices that don't both have the latest bluetooth version, or WiFi encryption or speed version, so they have to settle for the lowest common denominator?  Maybe you had a lightning connector phone and only had access to USB chargers, or the other way around?  Maybe you had an old 40 pin ipod or iphone connector and needed a special cable for it?  Maybe there's even one of those cables built into your car.  My point is digital standards change all the time and it causes compatibility to be a disaster.  If there's a genuine need for or benefit from doing so, certainly we should embrace it, I talked about this in a recent post, but that need and offer does not exist here.  USB has been around for less than 30 years and is already undergoing a change from Type A to Type C (and that's to say nothing of the many variations of mini, micro, and type B we've seen along the way).  Despite being one of modern computing's golden beacons of longevity and compatibility, it pales in comparison to the headphone jack.  The 3.5 mm jack on the other hand truly is universal and always works, always.  It would be very foolish to give up a great property like that for something that doesn't share it, particularly in the very ironic name of obsolescence.

The implication here (which is by no means a given) is that you'll get better sound by passing a digital signal to your headphones which then use their own DAC and amp that is of higher quality than what was in your phone.  While this is definitely possible, there are two issues that prevent this from being a bonus across the board: one, your headphones might not have a DAC and amp that are better than what was in your phone, and (more importantly) two, having a headphone jack does not prevent you from also offering this feature.  We don't need to trade one for the other.

It's really not difficult to look up a list of phones with IP 68 ratings and headphone jacks, most relevant here, the Samsung S10 and S10+, as well as the Samsung Note 9.  Companies would like nothing more than for us to have memories that short, it would make a lot of bad practices much easier for them, so please, try to fight it.