I think the main "issue" is that Apple won't be able to properly take their beholden 30% or whatever their fee is nowadays. A "wrapper" app has no real value by itself so they can't put a serious cost on it, but once it's on a user's device it can be used to create unlimited things of high value. Apple definitely doesn't want to miss out on taxing that value in their ecosystem, so it's easier to just block it and force devs to stick to apps with a appraisable value.