Yup, propane's vapor pressure is far greater than butane and isobutane and for one major difference, it doesn't require a preheat tube to work at subfreezing temps. I suspect a preheat type iso-pro burner would be quite dangerous with straight propane.

Once upon a time you could get a simple two-legged burner head that would work with a propane cylinder (forming the third leg of a tripod) for "backpacking." The burner itself was light but the cylinders are crazy heavy, again due to propane's high vapor pressure.