One aspect a lot of people are missing here is App Store review policy. I'm not defending Primal, but I can see how they've made a conscious choice to play in the field of what's possible under Apple's guidelines (and Google's too, to a lesser extent). If a NIP-60 wallet means the app won't be allowed on the App Store in most countries, that's a pretty big trade off. Can an app with a NIP-60 wallet and that allows zapping of posts get approved? It would require a LOT of finesse, and perhaps some in-app-purchase scaffolding too. Also sometimes apps need to reach a certain size before they face higher levels of scrutiny, so these idiosyncrasies can sneak up on newer dev teams.