I do it for services I don't care about. In my mind it is more privacy for me. Keeps you out of my real inbox and my password out of your system and I believe that I can - to some extend - remove myself without having to go through whatever crap account deletion process that services has tried to cobble together.

Worst offenders let me login with google and then immediately asks for name and phone number or email and asks me to verify it.

In general, I do understand that use of SSO is due to convenience. Especially since in many cases websites provide less friction when signing up via SSO instead of using username+password.

I am shocked, shocked, by the number of different K. Strauser people who have typed that email address into some random website or another. I've gotten bank notifications, loan documents, Facebook signup info, meeting minutes from some random volunteer work, and all kinds of other things. When I can figure out from context who the intended recipient is, I try to let them know so they can fix it. On one occasion, the person sent me back a swear-laden diatribe for "hacking their email". Sigh.

I think this has made me a better engineer, though. When someone says something in a meeting like "...as long as they type their email correctly", I can jump in and address that myth head-on. No, people will not type it correctly. If it's a minor pain in the neck for me, with an uncommon name, I can only imagine the traffic that the world's John Smith's get.