I have a Dremel VersaTip 2000 model, Butane flame tool. It does what most Butane torches do, but it’s mostly for soldering/desoldering things. It has tips to use it as a heat gun, like a narrowing tip for doing heat shrink tubing, and a large flat foil for heating up and removing paint. It has a heat deflector so you can use it for radiant heat, supposedly this is for low-temperature heat shrink tubing. I’ve used it to repair a hole that melted in a thermoplastic component on a lamp.
Theoretically, Heat Guns are supposed to be for heat shrink tubing, paint removal, and thermoplastic applications. But, as you can see from all these other responses, they are used for difficult situations, then put away until needed again.