It is one of those programs that is extremely helpful, yes. However, if you are just starting out, the main benefit of WDP is how it gives you an easier user interface to use for setting up your MFDs and countermeasures. Once that's done, you won't need to use WDP again until later, much later.
I use it now to generate Data Cards for missions I fly, helps me remember all the details of the flight. Kinda like a kneeboard...