If you own your email domain, it takes all of fifteen minutes to move to something like Fastmail. You just switch the MX records, run a GMail import, and you're done. Plus, Fastmail's UI is much faster than GMail's.
People are not used to email addresses with personal domains. I've had people get confused by my email address when I speak it to them. I've switched to just giving out my gmail address if I ever have to speak it instead of being able to write it down.
And developers don't account for custom domains when obscuring your email address. me@myfullname.tld is usually obscured as m**@myfullname.tld. That's pretty bad on password reset forms since it lets someone easily turn my username into my real name. If I had registered with myfullname@gmail.com, they'd get nothing interesting.
I've found if you use something like firstname@lastname.tld people generally get it if they've dealt with any other business email addresses (in some cases it actually makes you appear more professional). They usually have your first and last names before you get onto email addresses so they can piece it together and validate it.
If you're really worried about password resets showing your domain get a second domain and only use that for online transactions, it can then be as obscure as you like. Sure there's an extra cost to that but it's a trade off of cost vs the level of privacy you want.
Or, you're part of the 95-99% for whom email and the Internet is of critical importance but because of the ease of access, and the technical minutiae, and generally misplaced trust in corporations, you never learn why this might matter.
Sorry to say it, but I find your comment condescending.