Oh. Well, no duh.

Did they ever explain why this wasn't on by default before? Was there a practical reason for it at all? It's one of those things you do once and never think about again, but it's weird that you even had to.

I guess maybe they thought that having some games try to launch and fail by default would look bad? They've recently added compatibility ratings to non-SteamOS Linux systems, so maybe that's the difference now? Still a weirdly annoying choice originally, though.