Here is how it works. They press the pants, turn them inside out, put them on some type of fixture and run a small bead of silicone caulking along the crease. Yes, the same stuff you seal a bathtub with.
It basically hot glues the sides of the crease together. The problem is, if the silicone caulking gets squeezed through the fabric when they put it back on the hanger, it shows as a shines spot along the the crease. They ruined two of my three suits with this process. I was able to get most of it out of the third suit and they replaced the two they ruined. It just cost me two extra days of suit buying.
It is great if an artificially sharp crease appeals to you (imagine a security guard uniform) but not something you should ever do to a suit that you want to look classy or professional wearing. This is for bachelors who don't know any better or those who wear cheap scuffed shoes with there suits.
In summary, it is an up sell, it can ruin your suit pants, it makes a good wool fabric look like a pressed in polyester suit crease and, you should stay away from it. Oh, one more thing I learned, you need to be extra careful at the dry cleaner. If they press the suit with any varied crease from the traveler crease, it looks terrible and has to be redone. I.e. more wasted time.
To be clear, I researched the suit fabric and tailoring and will continue to shop at Jos A Bank as my primary clothier.