Unfortunately, Apple offers a very short menu of business models to the (iOS) app developer, most of which are absurd for the developer. The very sensible approach you suggest is called a "demo" or "free trial" version by Apple and explicitly forbidden. As you should know, clarky07, since I've learned quite a few interesting things about the life of an Apple dev from your much appreciated blog posts.
Ah but the only restriction is the app can't become a brick. He was still offering 1 a day, and could probably restrict that further and be perfectly fine under that rule. In my apps I limit the things you can save. You are welcome to delete them and save more, hence the app doesn't brick, but most people like to keep their data.
They have this rule, which they claim is one of their most common reasons for rejecting and app (from Apple.com):
NOT ENOUGH LASTING VALUE
If your app doesn’t offer much functionality or content, or only applies to a small niche market, it may not be approved.
This certainly suggests that the more you cut back, the more likely you are to end up rejected entirely at some point when you submit some unrelated bug-fix upgrade for approval.
It also suggests that iOS developers can't create useful apps that are just for their own family and friends. If Apple doesn't see the benefit to their other customers, your family and friends won't be allowed to have your app.
