In this case, it’s likely that they have set up recurring SEPA debit payments. Changing the payment provider won’t keep the revenue coming in - it would require every customer to sign up for debit again. And when stripe figures out the mess, you need to consolidate the two providers or you’ll end up debiting twice.

Looks like that might be the case. I might have been confusing Gumroad with Braintree. I was only attempting to give an example, not advocating for one specific processor.