Now playable:
Avatar: Frontiers of Pandora (desktop only)
Ball at Work: The Ultimate Speedrun Platformer!
Banyu Lintar Angin
Dinner with an Owl,
Farlight 84
Flatout 3
KinitoPET
Owl Observatory Dem...
What problems do you anticipate? Wine, which Proton is just a modified version of, implements file dialogs. If it didn't, just about every application that isn't a game would be broken. Needing to open files is pretty ubiquitous, after all. You need file dialogs for that.
Well part of what it does is grab your actual desktop background to use, and there's a couple different ways to do that on Linux afaik
Also I guess the file dialogs would open only to the wine prefix? My experience with wine applications and dialogs is mostly through bottles, so I'm not sure of the sandboxing...