Every app submitted to the App Store passes through guidelines covering privacy disclosures, in-app purchase rules and content standards, which is why certain payment flows or features look similar across unrelated apps.
Rejections are common even for established developers, often over minor metadata issues rather than functional bugs, which explains why some updates take longer to appear than developers announce.
These guidelines create consistency and a baseline of trust for users, though they have also drawn criticism from developers over fee structures and platform restrictions.