One bad thing about google fi is if you forget the google account password & email that you associate with the phone number and don't have a 'backup email' for it, it's near impossible to close the account or similar and have it stop charging your credit card until you do a chargeback. Which also means random people can charge your credit card on a subscription. Google support cannot do anything on their end to get g…
I have a Google account specifically for Fi, as uncorrelated as possible with any other Google accounts, enrolled in advanced protection, the idea being that I'm unlikely enough to lose access to the account that the additional security of _not_having a "come show us your ID in the shop" backdoor is a feature.