I've also heard - at least with Komondors - that they're to help the dog be accepted by the sheep and fool predators into not being sure when the dog is around, but I don't know how true that is. I don't doubt they do protect from predator attacks to some extent though - humans didn't invent gambesons densely packed with sheep's wool as padded armor because it doesn't work. Couldn't pay me to maintain one, though. I do groom my curly boys myself, but I wouldn't trust myself to keep up with the work well enough to keep the dog's skin healthy and hair low-odor.
Slightly related topic, but a breed I'm more familiar with, Lagotti have a less extreme version - sometimes called rustica - where the coat is essentially allowed to felt (with some minor maintenance to prevent matting close to the skin or in uncomfortable areas) and then given a total shave-down once or twice a year, no brushing required. Practical when they were working water dogs in marshlands, I'm sure, because they required so little upkeep and it's incredibly waterproof. Possibly less so once they were revived as a more specialized truffle hunting dog. But the feel of a 'felted' coat would drive me crazy. Frodo's never going to have a totally smooth coat that's easy to run a comb through, even with regular brushing and fancy conditioners/detangling products, and he develops some felts despite our best efforts unless we keep him really short. But the texture is very pleasant, not super soft but also not that super crisp feel you get with poodles who have a really nice coat, because unlike poodles he has an undercoat as well as the waterproof guard hairs. I imagine corded breeds to have a similar texture when kept shaved, though I've never felt one personally. Lagotti can be corded, but I've never seen one and only know it's possible because it's a DQ in the showring, haha.