Eh, it isn't bullshit except for the "capital" part. There's no capitals you a cultural zone because it's not something that can have a capital.
As an example, I'm in the southern Appalachian zone. And there's a distinct subculture here that's different from its surrounding regions. But Asheville? Not even close to being the center of the overall culture at all. The city and its immediate surroundings don't even match the rest of the region it's , in a lot of ways. You go from somewhere like mars hill nc, or mountain city Tennessee to Asheville, and it's a different world almost.
Same with Boone tbh.
There's differences across the mountains. Nc vs Tennessee, you find some things that are different, and both of those are different from the actual hill people, the ones way to in the mountains. And even that differs once you get up into west Virginia
So, Asheville being randomly picked as the capital for the region makes all the other picks questionable at best, bullshit at worst.
But the region is overall accurate. The edges are blurrier than the image shows, as there's shifts as you go from full on mountain folk, to those adjacent, to the actual foothills. You still keep a fairly distinctive sense of culture for sure, but there's a ton of bleed.
The other areas I've visited I can buy the general regions the map has, with the same caveat that without a major barrier, you'll get bleeding well into each distinct "border" on the map, with those border areas having a different vibe from their opposite side.