katrina,
You may have driven past our place north of Merriman. If so, some of those soapweeds were ours! Along the north edge of the sandhills, it is very sandy and choppy hills. It is so rough in places that a pickup cannot be driven through it.
That my friends is soapweed country. Not that our friend "Soapweed" would necessarily claim it, but rather, where they grow profusely. I can't think of any particular benefit to them other than they probably hold the sand from blowing.
It has been discussed on here, that cattle will eat soapweeds. We used to make them "grub" them many years ago. If you fed your cows cottonseed cake, it was supposed to make them really go after them. Our cows don't eat them today. I think it's because we keep them in better shape than 20-30 years ago and don't let them get hungry enough to be forced to eat them.
I couldn't tell much of a difference in the soapweed population after making the cows eat them. It may have stunted them some, but they are just as thick now as they ever were.