Seal (but don't insulate) crawl space?

I've got a crawl space that I'd like to seal, and wondering if it's crazy to just do that -- and skip insulating. The crawl space is reasonably warm and dry, but a radon system is going in soon. I think that will draw more air through there, and I'd like to prevent pipes in the crawlspace from freezing. Can I just use caulk or Great Stuff on the sill plate and rim joist, and skip the insulation step that most websites seem to show? I want to minimize the time I spend down there... Hardcore professional spray foam is probably not an option for me. I'm wondering if a quick seal-up job will make a nice dent in things. If I use Great Stuff, will that make my life harder if someday I do decide to insulate (I doubt that will happen, but who knows)?