Your android phone will continue to work as-if-offline if your account is banned. You can still do calls/sms and browse the web, but all google apps won't work until you create a new gmail account (and obviously you'll lose all your data).
How does this work when your account has been banned? Is my phone a brick afterwards? Someone should try this out.
When I had an Android (OnePlus) device I often factory reset when tinkering with it, go to bed and continue whatever I wanted to do on the next day. Of course my phone had it's bootloader unlocked and TWRP recovery, since I was trying to get lineageOS + spoofed signatures + microG to work.
So basically the scenario is: factory reset your phone, go to bed, wake up with banned google account, have a new brick decor for your garden.
Would be funny if they didn't think of this possibility.