Yes, Beth. They can be sharpened if you like.
Here's an example of of their use in conjunction with charcoal.
Or here using the black and white.
It would be rare for me not to use any in a pastel painting.
They are great for drawing, layering, knocking off too mush pastel, unifying color. Some people use them in the early layers (Daniel Greene for one) and some for the finishing work.