Ask HN: Why does Apple need to know how subscription fees will be used?

I've submitted an app for review that will be used with a companion, subscription based web app.

The submission was rejected because they needed to ask me some questions about my app. One of them really bothers me.

3) How does the user/company pay, is it subscription-based or lump-sum? What's the cost, what is it for, and what are the payment options?

I'm using stripe to take credit card payments but why does apple need to know how the money will be used? No payment will every be made inside the app itself.