There are other reasons to keep your @gmail, such as being a precaution in case you lose your domain as well as to use it for into your DNS/registrar account since using your domain's email to manage the DNS or domain itself is a bad idea in case DNS breaks email deliverability.

> having my own domain makes me look like a complete nerd to my friends.

...yes, of course; why else would you do it? ;)

I'm semi-kidding; there are very real practical benefits, but I really do run email through my own domain, at least in part, because it sends a message.

I have the same sentiment, but I think using other appropriately-named providers has the same effect. Nobody bats an eye when you say @fastmail.com or @mailbox.org for example.