Google does not allow anyone else to register the name ever again, so there's no risk of identity theft. The main reason is to remove cruft I don't need or use.
That is good to know, thanks. Someone in Google gave me an invite three years before GMail was formally released publicly, so I have my name. There might be a point when I cancel my account and it would be great to be protected from someone claiming my old email address.
I like paid for Google services like GCP, Play movies and books, etc., but I want my online identity and all communications to be through my domain.