Yes, that could be useful and I could consider switching to such a service if it was available. I would worry though about giving total control over my subscribers to some outer service that might hike up their prices suddenly.
It would be nice though if someone else dealt with all the different payment buttons, subscription management and just wired me a lump sum monthly and sent the PDF for address labels that I need to print out for shipping.
I could use a cheaper sending option and that would really boost the profit. That would introduce an initial delay for the subscription start, but of course after that it would not be noticeable for the subscriber.
One time I was experimenting with sending first package using airmail and subsequent packages simultaneously using the cheaper shipping option that was supposed to be 2 weeks slower. But in reality the slower one arrived first and the faster one a day later, leaving subscribers confused.
It would be nice though if someone else dealt with all the different payment buttons, subscription management and just wired me a lump sum monthly and sent the PDF for address labels that I need to print out for shipping.