It’s good for email and personal sites (those aren’t dead, but they’re more popular for people that either write a lot or are self-employed). I’d only use a personal domain for self hosted apps if the users are just you and your family.
For something like hosting Lemmy, with users you don’t know, I wouldn’t use the same domain as where you host your other personal stuff, even if it’s not your name.
My homeserver runs Debian with Freedombox, and I’m using their GnuDIP ddns service, but it’s for free subdomains, not your own.
I used to have a script to update my own domain in Gandi console. I only stopped because I didn’t really need a domain for my home.