[tomschwiha]

I personally have my personal email as Google account email, so even when I lose my access to google I am still in control of my domain (and email).

[edoceo]

And still couldn't sign-in-with-google. On an email linked that way, so no password recovery. Would likely be a new account - with bonus "that address is already in use" problem.

[tomschwiha]

I agree, there may be an additional step necessary if the page doesn't handle this case already, but this way you can still prove (more easily) ownership to the support.