Camping-type shelters are typically going to be more short-term than a car or camper simply because they’re not constructed to last very long (and they’re usually not insulated or climate controlled, making them unpleasant to live in for a long period of time). They’re also dependent on having access to land, which can be non-existent in some parts of the country or in great abundance elsewhere.
When looking for land for a short-term, temporary shelter, there are more options available than if you need land for a traditional house. Perhaps a friend or family member owns some wooded or overgrown land where you can build a shelter out of sight of prying eyes. Or maybe there is government or vacant land in your area where you can safely squat for a while. Or you may have a piece of rural land that you own, but you need a temporary shelter to live in while you build (or save up for) something nicer and more permanent.
Camping shelters are also a benefit if they’re something you need just periodically. I read once about a woman who had a friend with an apartment, but the friend wasn’t in it most of the time because she traveled so much for work. So she let this woman stay in it while she was out of town. The woman had to find her own accommodations when the friend came home, but most of the time she was able to live there rent-free. If land was available to this woman, then one of these camping shelters might have been a free place to stay on the weekends when her friend came home. (She wouldn’t raise as many suspicions, either, by only being there part-time; it would look like nothing more than someone camping.)
One benefit to a camping shelter over a micro-camper or sleeping in a personal vehicle is that you can build it large enough for two people to live in reasonably comfortable, so if you have so far been dismissing alternative housing ideas because you are part of a couple and the idea of wedging two people—especially two tall people—into a vehicle makes you shudder with a ripple of claustrophobia, then maybe a camping shelter is a better option.
There are a variety of camping shelters, depending on available materials, the terrain and climate, wildlife (or human) threats, how stealth you want it to be, and your construction skill. They can be thrown up in one day by one person, or may take weeks and more than one person to assemble. You will have to judge which is right for your situation.
Is this a little too primitive for you? Check out other affordable short-term and permanent housing options: Why You Should Consider Housing Alternatives