Apple's App Store Review Guidelines have recently been updated with a section dedicated to cryptocurrencies. In sum, Apple's app stores (iOS, macOS, watchOS, and tvOS) will no longer allow apps that create or generate cryptocurrencies. Crypto wallets and trading apps are still kosher to distribute, but the rules surrounding these kinds of apps have become much more strict.
https://www.notebookcheck.net/Apple-bans-crypto-mining-apps-from-all-its-platforms.308550.0.html