Well, we talked about that possibility. There was one person here who argued for having algorithm purchases be for only a single stompbox and to have them tied to that stompbox. But that wasn't possible given the way Apple's iTunes Connect works. If you buy something via in app purchasing once, you can't buy it again. So, if you had multiple H9s, you could only buy Shimmer for example once for one of them. We also thought that would violate Apple's rules, although what we're doing is so out of the ordinary it was hard for us to be sure about how their rules applied in our case.
For that reason and also for reasons of fairness, we wanted algorithm purchases to be unlocked on all of the H9s registered to your account. But when you start thinking about allowing purchases to be unlocked on multiple devices, you have to start worrying about fraud and misuse scenarios, and that's when you start getting into scenarios where you need to delete algorithms from stompboxes.
We have a long document talking about all of these issues and I don't really want to rehash all of that in a forum post. But I will say we thought about this problem a lot, and we came up with the best solution we could given the constraints we were working under. We aren't perfectly happy with some of those constraints either, but at this point, it is what it is.