You are, of course, aware of the privacy guidelines in the Review Guidelines, particularly section 5.1.1:(ii) If your app doesn’t include significant account-based features, let people use it without a log-in. Apps may not require users to enter personal information to function, except when directly relevant to the core functionality of the app or required by law. If your core app functionality is not related to a specific social network (e.g. Facebook, WeChat, Weibo, Twitter, etc.), you must provide access without a login or via another mechanism. Pulling basic profile information, sharing to the social network, or inviting friends to use the app are not considered core app functionality.So your statement the app is unusable without an account may be another problem for you entirely.
Topic:
App Store Distribution & Marketing
SubTopic:
App Review
Tags: