oroalej

because it's changing soon, mostly a mistake on my own side

It's all about the bandwidth, PCI-E 3.0 is capable of up to 8GB per sec on each lane... So if you've got a card in a 16x PCI-E 3.0 slot that's a theoretical limit of 128GB per sec.
 
PCI-E 4.0 has a bandwidth of 16GB per sec across each lane, which gives you 256GB on a 16x slot.
 
PCI-E 5.0 is slated to be released in the next year or so, which doubles bandwidth again.
 
So the latest 2080Ti doesn't yet max out the PCI-E 3 bandwidth... so whilst it's not essential and won;t be for a couple of years... It's all about the bragging rights... AMD have launched the first PCI-E graphics cards, along with the first 16/32 core consumer desktop CPU's and all whilst being the first to do so on a 7nm production.
 
So whilst you won't see any immediate benefit to it... it is the future of gaming cards and storage devices. Think of it much the same way nvidia touted RTX... no real benefit to gamers, as very few games support it (9-10 months later there's still only a few with another few being released in the coming year)... and outside of the 2080 series... not really worth having at all because of the performance hit... even the 2080 series itself is only gonna give you around 60fps with it on... which is around a 50% performance hit I think.
 
Within the next 12 months or so... nVidia will be releasing their cards with PCI-E 4 spec and intel motherboards will start getting it as well... or they face the risk of looking like they're being left behind with 'older' technology. Much like they are in the CPU market when they haven't even been able to bring 10nm CPU's to market (I think they are later this year) whilst AMD are already on 7nm.
 
At the moment, it's only X570 boards that get PCI-E 4... I've heard nothing about any B550 boards coming along any time soon... and I still don't know for certain if asll of the B450 boards can support the 16/32 core R3950X.
 
So... tl:dr  no immediate benefit to gamers, but future proofing your tech and AMD claim several world firsts over intel & nvidia.

Noob here, can you explain why GPU cannot utilize the PCI 3.0 lanes? How can the GPU utilize it? Thanks for answering