As someone who has been skeptical of Proton and avoided their services because it seemed too good to last (or be true), this really boosts my faith in them.
Not saying I’m going to stop self-hosting my own mail, etc. or become a customer tomorrow, but I’m much more likely to recommend them to friends and family who ask, and will absolutely keep them in mind for myself if I ever do have a need.
I’ve been using Syncthing-Fork (on F-Droid) for the extra features it has. I wonder if that developer will be able to continue.