I think tying remote access to a subscription would not be a great idea, but many people lack the internet performance or reliability to stream files from their homes. Often it’s very difficult or impossible due to how ISPs implement firewalls and NAT.
For those people who don’t have super lenient and reliable gigabit connections at home, using your “backup” as a digital locker may be a good way to make it perform well.
I’m starting to see this less as a “backup” feature and more of a new product with multiple benefits (offsite backup, mobile access, online storage, maybe more?). This also makes the product appealing to a larger group of people, which makes it a more commercially viable project. Even if you don’t make use of every use case, it’s still valid product for many more people.