Why not just subscriptions with random persistent pay reference? They could be safe against adversary that has access to Mullvad data, while still offering con

Why not just subscriptions with random persistent pay reference? They could be safe against adversary that has access to Mullvad data, while still offering convenience of subscriptions. It is not safe against adversary that has access to banking data, but even independent payments are not safe against that adversary, if they are often enough.