I first heard about this on the DL and TWIL podcasts. There's some concern that this will take away from having developers port their games to native Linux versions with Steam, if they can just port to — or even write natively for — Proton instead. That would also be true for macOS ports.
However, if this could eventually help to break the stranglehold that Microsoft and Sony have, I think it's a very good thing.
However, if this could eventually help to break the stranglehold that Microsoft and Sony have, I think it's a very good thing.