I mean sure if you want it to be art then it can be. But that's not typically its primary purpose. And the skills required to make a UI good for its primary purpose (usable, easy to understand, etc) are quite different from those required to make good art.
In other words, a UI as an artifact might be art. But UI design as process is different to the creation of art as a process. You could do both, but they're mostly orthogonal.
I have little respect for "artists" who do UI because the job requires little skill.
Sites and exposes like the parent of this entire thread serve to inflate the worth of people who do this stuff.
Painting the mona lisa is talent. Arranging text and pictures with flat colored geometric elements is NOT talent.
The idea that the still life painting is even comparable to some website design is laughable. It takes a lot of skill to be able to create that painting, it takes almost no skill to devise the layout to that site.
This is where we disagree. It requires little skill to do it well.
Minimal/simple/clean designs are not only simple visually but simple from a intelligence and effort standpoint.
There are many UI designers/programmers but their aren't many Character artists/programmers, 3D artists/programmers, animators/programmers, concept artist/programmers.
The reason is the latter examples are two freaking incredibly hard skills to combine. The former dual skill set is common because UI design is extremely trivial compared to the later skill sets.
Who are you to say what is and is not art?