Self-hosting has the added advantage of offering "unlimited" storage space, as many addresses using whatever creative schemes you want - I give specific addresses to all commercial/government/organisational institutions I communicate with which allows me to spot who abuses or leaks addresses and makes it possible to block those and only those addresses. SMTP and IMAP have their warts but they remain among the few well-specified open protocols which enable communication with anyone who can follow the standards. Any "successor" to these better be just as open, well-specified and preferably backwards-compatible with SMTP or it probably won't fly.
Not unless you can tie the use of an email provider to a protected characteristic (race, gender, etc.)
(though that one at least I legitimately chide people for using, because I have family members whose devices got infected because juno failed to filter out malicious emails appearing to come from personal contacts).
I still use yahoo.
But somewhere someplace, I cannot trust them on security anymore. I know of a few vulnerabilities that I cannot explain. And so my emails will remain for insecure purposes.
Because every time I read about yahoo on HN it seems to be only negative opinions and in general people look funny at you when they see you with an yahoo email address instead of a Gmail one which has become the norm for average joe consumers.
I mean I know they're not a sexy company anymore and they didn't have a competent CEO but their e-mail offering still slaps IMO.
I use it mostly for non-critical activates like signing up to websites and online shopping.
That's the only problem I have after migrating to Fastmail: it takes serious effort to make people over the phone understand that I have an email in a different domain. I can spell it letter by letter, but people often still can't figure just where this funny thing I'm dictating should be put. There's a problem with @ sign, too - somehow, people tend to forget it exists. Well, it exists to separate user from domain, and since they don't know the domain part exists, they don't need to know about the separator I guess.
TLDR: if not on GMail, you need to make a habit of sending the address in an SMS, forgo all hopes of giving it to someone over the phone.