Proton Drive is online-only so I’m not sure what you’re asking here. Are you asking if you can download files?
The Google Drive app lets you save a file locally so that you can view it offline. I mean under the hood it is just downloading and syncing, but it’s a lot nicer than having to manage the files you want to view offline yourself.
That’s a big negative.
Why? Desktop file backup seems like a pretty similar feature to mobile photo backup (which seems to be working for me).
Edit: also looking at some videos of the Windows client, folder syncing seems to be possible. Just not yet on Linux. Still not sure why it would be bad.
Ah, got it.