I have watercolor crayons and watercolor pencils and markers and a few gelatos. They all work in the same manner. If you have gelatos you can use them directly on the stamps, then spritz, and then stamp. The watercolor colors are great for making a background. I find it hard to do fine lines with them so I mostly use my watercolor pencils or markers for images and the watercolor crayons for backgrounds. To me they are all so similar that a person could use them interchangeably if you were good with them. None of them are what is considered permanent, if using underneath something if the top something uses water the colors will move. The only watercolor pencils that are permanent are Inktense pencils after they are dry. Even gel medium will move gelatos, watercolor pencils and pens, and watercolor crayons around after they are dry.
As far as I can tell watercolor anything (gelatos, crayons, pencils, distress ink, dylusions spray, watercolor markers, watercolor paints) will all move if you put more wet medium on top. The only things that are permanent are Inktense pencils, acrylic paints, and different brands of alcohol pens.
If you already have gelatos you can do everything with those that you could do with watercolor crayons. The watercolor markers do work really well on stamps.