I can understand your concern, but realize that some of us have been successfully using them for years, and for more than just drying paint, that they've become invaluable tools in our arsenal. They allow a level of economy to your building that you can't put a price on. What price is your free time?
Some of us work better under a bit of pressure, and like to get a lot accomplished in a short amount of time. While the body is drying in the dehydrator, the other bits can be worked on during the same session in one evening, not simply over a week. If you've never done a "speed build" of a model, you may not realize how much the dehydrator fits the success of such models. It allows you to do more within a limited time. Same can be said for superglue used w/accelerators. That was another tool that greatly sped up my building pace. Allows me to build quicker, and spend more time contemplating other more tricky areas, like suspension settings and wheel locations that require more thought. Anything that can save you time in one area allows you to spend less time building, or more time on other areas. Done properly, your models will improve.
Also don't forget how real automobiles have been baked in the factory to speed up production. It's perfectly okay to bake paint at an appropriate temperature to speed it's drying. Catalyzed epoxy or urethane paints dry by chemical reaction, but that's not how model cars are generally painted and it's very dangerous stuff to breath.
A dehydrator speeds up drying. It speeds up drying of small parts, like taillights/lenses. It speeds up the curing of putty and primer. It speeds up the curing of decals, and if you're applying multiple decals which require a lot of painstaking time, this really saves time. It warms your paint/bodies before and after spraying.
Anyway, I'd be lost w/o the two things that really sped up my building, the superglue/kicker and my dehydrator. W/o them I'd feel like I was back in the dark ages, and my build rate would suffer a lot. I can't think of anyone who has bought or made a dehydrator that hasn't adopted it to the point that it hasn't become one of their most important tools. Seems like the satisfaction index for them is quite high.