Stripe requires a different flow to add a Bacs payment method, whether it’s simply associating the payment method with a user or using it for a deferred payment on a subscription with a free trial.

Using Checkout Sessions to create the Bacs payment method solves both issues. However, we still need to define the exact flow. In the case of purchasing a subscription with a free trial, we need to determine whether use a dedicated button within the payment method selector to redirect the user, or handle it automatically after submitting the form.