Frankly, this sounds like a long-winded way of saying "you write a check," with a technical difference being that the transaction is a push from the sender rather than a pull from the recipient. If this form has an option for recurring on a (e.g.) monthly basis, then it's what Mullvad could suggest subscribers switch to, if both parties have a SEPA presence.
Yes, monthly SEPA payments (with a static amount and static reference/message) are a commonly used service at least in Finland, for e.g. paying rent between private individuals, and it works as-is with Mullvad wire transfers.
