It's primarily useful to us animators, Jackson. Particularly if we want to animate props and characters that interact realistically with one another. Sure, we could keyframe it all manually, but this is faster. It's a time-saving tool, like Mimic.

For non-animators, it probably isn't as useful. But one could conceivably use the ragdoll function to drop a character onto an object (for instance, a couch or the floor), in a fraction of the time it would take to create a realistic pose by hand.