It allows you to rotate feet into any position!
Why is this useful, I dunno... but it was a request!
The latest iteration was also a separate request, made into a reality by rob55rod. It allows feet to be placed just like any other part, and unlike the previous iteration, they don't behave like mouths. Additionally, when used alongside Spore Stacker, this mod allows for feet to be placed on anything, just like details.
Download here
A separate mod with an identical effect on graspers can be obtained here:
Download for hands here
Old versions: