It's not just that. As a developer I wouldn't want Apple to know who my paying customers are. Right now, there is no option. With this hopefully there will be more options.
I, as a customer, don't want to pay many companies directly. The prime example is any news publication. There are many I'd happily pay for except (like gym memberships it seems) it can be incredibly difficult to cancel. I won't reward that model so they get none of my money.
I'm fine paying companies directly, but I don't want them to manage my subscriptions