Depends. What do you think are using most of the people? I would wager something like gmail or outlook. So, even if you pay for an encrypted provider, chances are, 99% of your mail is unencrypted on some untrusted servers.
If I have to communicate securely I use signal.
Purelymail gives me the benefit of beeing super cheap and giving me many options on how to access my mails. Plus I can easily share my domain with my family.
Yes that is true, but he lists every downtime with a analysis. And I am okay, with his track record. Plus, if he decides it is no longer worth his time or the bus gets to him, I just move my domain to another provider and dont suffer much. Plus he uses aws, so the infrastructure in itself should be pretty reliable.