OAUTH2 google doesn't seem to give you refresh tokens easily
If you run the authorization_code flow to obtain an access token from google I find the response often doesn't contain a refresh token, so then it can't really be used for cron jobs.
There was some suggestion that you have to delete the token in the civi admin AND at google. This issue suggests it only gives a refresh token when you are prompted for consent and not subsequent times (or if you pass the prompt=consent parameter).
It may only come up as a problem during a testing cycle where you keep failing and re-requesting, and for people who are setting up an account and get it right the first time it won't be a problem.
TBD