As a developer / sysadmin who used to host his own mail and uses complicated half insane APIs every day, I know that even things that are reliable and easy to set up (such as debian servers) require maintenance and all the work and planning that goes into making something secure, reliable, and performant.
I don't see how anyone with experience could contend with a straight face that running a network service like email is a set-and-forget proposition. I remember having to brush up on my mail stack every time I needed to troubleshoot a problem, and over time it became clear that I had over-prioritized hosting my own email.
Edit: It's a fine hobby project though, as long as you're honest with yourself about what you're undertaking.
(2) set up mail server, create account(s)
(3) reset public email account with domain registrar + hosting facility to newly set-up email addresses
(4) kill public email account
You only need one for a very short while to bootstrap your own email server, you don't need it forever.
But I'll bite, if your mail server goes down - and it will - you now have no email. You can't email your hosting support. You try to log in to your host control panel to do a reboot or raise a ticket but forgot your password. You can't get the reset email. Somehow you manage to login and raise a ticket but won't get any email notifications when the technician responds asking for your server id number...