Quick feedback with minimal effort is the name of the game in prototyping. The Selector form lets you add a sophisticated query by example form to your application in just a few minutes. That makes it ideal for prototyping. You can add the form to your program, show it to users, and see what they think. Then if the users don't like the form, you can discard it without having wasted a lot of effort. Even better, the users might like the form the way it is. In that case you can move on to more important things like building a really cool splash screen and hiding "Easter Eggs" in the program's about dialog.