To me, that's worth paying a little bit of money. My threat model is certainly different than yours - everyone's is unique - but I do sometimes need to share sensitive documents with friends and family, and I'm glad to have PGP to facilitate that, and frankly I prefer to have library renewal notices and commerce receipts encrypted automatically with my public key as soon as they arrive.

Posteo and Mailbox both start at 1€ monthly which is pretty far from 'a lot of money' for most folks using Apple devices.

With Proton or Posteo or Mailbox or any other service that supports auto-encryption with your public key when emails are received, the service loses the ability to read the email the moment the cleartext version is discarded.

Click to expand.Certainly everyone is free to choose which email service they use, but I do think it's worth pointing out that Proton has a free plan which has a reasonable amount of email storage to go along with it (1GB), and that emails stored on Apple's servers are still susceptible to an insider attack unless you have manually set up PGP - and in that case, only emails that you've received from senders that are also using PGP.

Personal proton email address