The only major company I know that even has the option for PGP on email is Facebook. It works quite well and was pretty easy to set up, so long as you don't use a webmail client or your phone.

some crypto exchanges do

Kraken does.

Encrypting your "here's your trade confirmation for ACME" and "you were late on your credit card payment" from your email provider would be good.

Even Facebook does. Facebook.