the issue with "encrypted email" is that there's no interop, which means that in a practical sense none of your emails are encrypted in transit. the only thing providers like tuta and proton provide is encryption at rest, which is not so valuable when the NSA has active programs that monitor all email traffic in the united states (and in many other places!)
in other words, if you want something sent via email to be secure, use PGP yourself or put the secure content on a dedicated platform
oh, and both tuta's and proton's clients suck
