If you count G-sync monitors as gaming monitors then it makes a ton of sense, I'm going to have to switch from AMD to Nvidia just because its so good.
I use a RoG motherboard because it has a lot of features, but mostly because it looks nice. There are some overclocking accessories for RoG motherboards if you really want that sort of thing.
Paying premium for "gaming" headsets or keyboards should solely be for aesthetics. Aesthetics is an important factor for some people, so for them I guess it does make sense!
Also totally agree that 60hz ISP is better than 144hz TN but whatever floats your boat.