I don’t mind paying for the domain name so much but I do mind the fact that even after paying for the domain name, there is no guarantee of having full control over the domain name. I do mind that even after spending money year after year, we are only renting a domain name, with the possibility of the domain name being taken away from us anytime!
I used to be a big proponent of hosting your email address at your own domain name. But then I had a very unpleasant experience of losing my domain name several years ago, for no fault of mine, due to anti-malware operations completely unrelated to my website. After that incident, I am not so sure!
I have written more about that incident here:
https://susam.net/sinkholed.html
I wish the mainstream World Wide Web were built around the concept of owning a domain name where we could prove our ownership using a private key.