Dude, same. I cannot understand it (for games. I’m sure people have valid reasons if they’re using the Deck for some other purpose). It seems there is a cohort of otherwise relatively tech savvy people who are just terrified of all things “Linux.”
Maybe they heard horror stories from friends or family while growing up and aren’t aware of just how close to complete compatibility Proton is. In fact, in some cases, it can somehow run games better than if one were to dual boot and install in Windows.
Even Valve’s own Steam Deck verification should be taken with a grain of salt, it seems as though they’re being extra conservative with those. I’ve gotten several "unsupported " games working (very easily), for example , Dark Souls: Prepare to Die edition is listed on Steam as “unsupported,” but it works great (with DSFix even) on my Deck.
ProtonDB is a far better resource for anyone reading this who hadn’t heard of it.
But yeah, it’s almost like this subconscious aversion to Linux. And they want to be in their comfort zone I guess.