Remove option to change card on file when stripe isn't the deafult payment method
If the default payment method is not set to Stripe and the client tries to add a credit card to their account it will not save. If I add a card in the admin it will also not save to stripe. If neither of these options work, they should not be available as options. Either disable them in this scenario or have a note on the page so that people don't attempt to save a card and then can't tell why it didn't work.
The current functionality is that it will delete the card on file but not save the new card. The page doesn't say that there has been an error or that the card has not been saved. This is deceptive.
Support said that this is the way stripe works, but I think you could find a better solution because the old 3rd party stripe module didn't have this problem. They had created a solution where the card could be saved/updated even if you weren't immediately charging an invoice.