My question is mostly for games available on Steam that you would still prefer to play on Switch. I imagine performance should be better on the deck for native/proton games, but there might be something else I am missing.
If I already own the game on either platform, that's where I'll play it. I also don't emulate the Switch on Deck, as (and although) I have a modded V1 that I can OC and a Lite for portability's sake.
I especially prefer playing TATE Mode shmups on Switch with my Flip Grip, it's a game changer.
I also tend to favour physical games overall, so I might buy games on Switch more often than not (unless there are significant performance differences).