One of their examples was a social network app that was rejected for including a crypto tipping feature.
This was detailed on an Apple support page for an app submission:
Guideline 3.1.5 - Business - Payments - Cryptocurrencies
Your app facilitates the transmission of a virtual currency but was not submitted by a corresponding exchange or recognized financial institution.
Next Steps
To resolve this issue, please provide documentary evidence demonstrating you have the necessary licenses and permissions to distribute an app with cryptocurrency exchange features in all the locations where your app is currently available.I can't imagine Apple's allergy to crypto payments is anything other than an insurance policy against the likes of Epic getting ideas to launch a cryptocurrency, which conveniently can be used to pay for in-app digital goods, circumventing the holy 30% tithe that is due to Apple.
Apple’s pitch from day one has been that the App Store is more trustworthy: it launched in the era where a common joke this time of year was going to have thanksgiving with your parents and removing all of the malware they’d installed on the home PC. Part of the justification for the restrictions on developers was explicitly that they’d benefit from being in a place customers trust, kind of like how much effort companies will spend to get a prestige retailer to carry their lineup.
> can't imagine Apple's allergy to crypto payments is anything other than an insurance policy against the likes of Epic getting ideas to launch a cryptocurrency
This wouldn’t change the situation so there’s no reason to believe this is intended to be some 5-dimensional chess game rather than a simple desire not to play in a scammy space with a much higher risk of complaints and regulatory issues.
I've no doubt that Apple would like to lock down the web too, but they don't have the clout to unilaterally change the internet. They can unilaterally do whatever they want to iOS though.