To be honest I am surprised WeChat is even allowed in the iOS app store with its all-in-one multi app experience, since app experiences of that type are explicitly called out as disallowed in the app store guidelines section 2.5.8 - https://developer.apple.com/app-store/review/guidelines/
(Actually, I'm not that surprised, they're probably too big to fail and Apple really wants to sell iOS devices in China)
(Actually, I'm not that surprised, they're probably too big to fail and Apple really wants to sell iOS devices in China)