If you would use SEPA for an SAAS registration, how would you handle the waiting time of multiple days? Accept the customer without prove of payment or ask him to come back in a few days?
For SaaS it's easy, you just treat the payment as a success. If it ends up failing, you treat it as a chargeback.
For selling goods that you hand over (e.g. irrevocable product keys) it's much trickier and depends on the specific business whether it makes sense to have the customer wait.
