It is pretty relevant...How do you objectively measure a "better UX"? IMO , there is no better measure than the users voting with their wallets (ie purchasing the app) .
In my experience, all these dribbble orgasm inducing designs just don't matter. Sure they may get your app featured by Apple, but good luck building a business based on winning that lottery. As an experiment, go on iTunes and tell me how many of the top non-games features a design with so-called better UX.
My simple theory of iOS UX design? Do shit that users expect!!
This is a marketing problem. If your designer is posting on Dribbble, your app is definitely being seen; my iOS concepts get more views than anything because that's what people are searching for these days. People may like the design, but may not have a reason to actually download it.
In the same vein, all of these "pretty app UI" sites rely heavily on submissions. If you think you have an app worth looking at that could possibly convert eyes to sales, submit them to these sites.
Additionally, "Doing what users expect" doesn't always have a straight-forward answer.
I agree that "better UX" is entirely subjective, and I didn't mean to imply otherwise. My point was that this is a UX-centric discussion and a mini-rant about advertising and marketing isn't really germane.