Since this thread gain a little traction, I should clarify:
Proton Mail has done some good technical work AFAICT. I appreciate the effort to make E2EE more usable and more broadly accessible. I’m not so sure it’s a good idea to blur the boundary between “E2EE” and “not E2EE” as their product does, but respect for the heavy lifting they’ve done.
I’m not saying their product is a total hoax or anything! I’m just saying that •in practice•, the actual benefits aren’t as large as you might assume.