The main reasons for me that I stopped using my own domain: - some sites will just silently refuse to accept addresses on unknown domains and signing up becomes impossible - worse, some sites accept it for sign up, but later on refuse to send a password reset - every time you have you write down or say out our your email address to a non-technical person, you are then obligated to host a mini Q&A on domain names and…
I've had all of these issues and more but only with my address that uses an unusual TLD.
As a joke I've considered creating an inbox at something like atdot@atdotatdot.com just so I can cause havoc when someone freaks out over my address or the subsequent use of NATO phonetics over the phone.