The UI will show up in every screen shot and video people put out. I don't think the UI matches the painted style.
Perhaps it is merely the crisp bright colors, but it looks out of place. Something as simple as running the UI assets through a style transfer could be another easy option to make it look more painted.
Personally I don't care much about the diffence, I just focus much more on the world than the UI. But yeah, the UI is definitely still work in progress (or rather, a grey box version).
Definitely looking forward to when they can put some manpower into the UI. I don't like the "tech" feel of it right now, really hoping for more of a fantasy style.