I recognize the fact that the argument is exactly the same as for not opening up the appstore in the first place. But the importance and scope of it is less if the store is open.

Now you can chose to buy en expensive device (or you did in the past and can't de-apple due to lock-in) or not. In the future you could chose not to buy photoshop because of their insistence on their app store dependency.

I think having a more granular choice is good. Like I said, that UX hit, imo, is less important than the monopolistic behavior displayed now:

The apple "tax" (including the rules around links to donation pages and similar nonsense). Curation that cannot be overridden by end-users. Unpredictable policy changes for developers. 1st party appropriation of successful independent applications. Unfair competing (think browser javascript engines).

I think bad UX is less important than those things listed above, that's the argument.