[yorwba]

Most of that area is covered by mountains or desert, and there are only about 22 million people living there. The economy also isn't terribly developed (although IIRC it's the fastest-growing among all Chinese provinces) and it's not exactly popular as a tourist destination.

That doesn't mean there's no reason to ever visit, just that there aren't very many more reasons than for e.g. visiting the neighboring Kazakhstan. Most people crossing the border and getting subjected to the surveillance are probably ethnic Kazakhs living on either side, visiting relatives on the other.