If you want really good looking scenery, static grass is a must. It adds a very realistic element to otherwise boring plain ground foam. Like weathering, it's about having a few different textures as well as colors. What's nice about having an applicator, is you can make your own tufts as well. The tufts alone are quite expensive if you buy them pre packaged. Look around YouTube and you will find some very cool ideas 
Remember: Like most things, you get what you pay for. If you use different lengths static grass, 2mm, 4mm, 6mm, etc, it's best to have the different size screens for your applicator. The fine mesh screen doesn't work very well with 6mm or longer grass.
You can always throw it up for sale when you're done with it too
