One example would be state disability programs, they already need my real name and identity to work with me. Are there any downsides to sharing a simplelogin alias containing my real name vs no containing my real name? I just think it would be easier record keeping for them.
Tracking just sender/recipient needs way less storage than saving entire mails, HTML, Images etc.
So if you have your name in the address, and you communicate with shit servers, it will be saved for sure.
If not, then maybe not.
Data protection policies might be different, as well. ProtonMail, for example, uses end-to-end encryption for email bodies, but does not encrypt metadata, which includes the sender, recipient, and the rest of the email headers.
This is standard PGP but kind of done automatically as people are lazy. And Thunderbird could be better, AND there is no maintained PGP on Android?