I use a steamer when I install carpets, suspended style headliners, new seat covers, (especially headrest covers) tonneau's, motobike seat covers, conv. tops, vinyl roofs, & many other things. Most materials can be stretched to form fit the project with a bit of heat. Wrinkles can be removed from things like conv. tops or headliners that have been folded up in a box for extended lengths of time. Just because those things are new, doesn't mean that they were made the day before they were shipped. Some of that stuff could have been sitting on a shelf for a very long time, in the box, folded up. The moist heat of the steam will remove that without worry of melting or burning the material.
When I do camper cushions that are to be recovered only, I can steam the foam to bring it back to it's original shape. After all this time doing this, I still find it fascinating to watch the foam 'grow' back from all the places it's been compressed for years, such as all the edges & corners. Makes the new covers I just made, fit oh-so-well!
I can use a heat gun for a lot of this stuff, (not on foam, though.) but they can cause probs. I've had an employee install a nice new conv. top on a '62 T-bird. Beauty job, but it had a couple of minor wrinkles in the sail panel on the driver's side. Instead of using the steamer, he was using a heat gun to get those out. One moment of inattention, (not concentrating, talking to someone, or whatever) & he had melted the grain in the top's material about the size of a fist. It's phukt & I can't have that go out the door! So I had to work all night to remove the top, & install another one. I had already told the customer that he could pickup his vehicle in the A.M!
I've also used the steamer to clean floors! I don't always remove my boots to run in the house. The steamer helps to remove glue & grease from both tile & carpets. Works excellent to remove mildew in shower stall grout.
I've also used them for their original intent. Drapes outa the wash, hung up, then hit with the steamer makes them hang like new! (yea, I'm that domesticated!) I have a collection of about 120 silk Hawai'ian shirts. I don't have an iron, (I refuse to own one!) but with the steamer they can look like they just came from the dry-cleaners. Absolutely no wrinkles! Works great on jeans left in the dryer overnight too.