Many counties are actually fine with people living full time in their cabins. It's the opposite that's problematic, using normal housing as cabins. But as you say, it can be an expensive and troublesome way to live, compared to buying something zoned properly.
there's also the matter of your person registry information being wrong all the time (since it has to be tied to something zoned as a primary residence). would be death by a thousand cuts since so many services and programs refer to this registry to automate things.