"Jumping" Pull-Ups: Worthless?

Over the years I've been a defender of CrossFit and many of its exercises, even certain styles of kipping pull-ups, which have their place for advanced competitive CrossFitters.

But one exercise I just don't understand is the jumping pull-up. I'm not taking about jumping from the floor to grab the bar then pulling yourself up, which can have some value. Here's what I'm referring to:

In some CrossFit classes you have the option to "scale down" if you can't do an exercise as prescribed. Let's say you have pull-ups in a WOD. If you can't do pull-ups, instructors normally have you do banded pull-ups. But some people are too weak (or heavy) for those. What do they do then?

The coach puts a box below the pull-up bar. The person stands on the box with his or her hands grabbing the pull-up bar. They're instructed to "jump and pull" until their chin is above the bar.

The problem is that because of the height of the bar, most people don't have to do any pulling work to get their chin over it. They're basically just standing on the box and hopping while holding the bar.

This doesn't do anything, though I suppose it burns more calories than sitting the exercise out. But the small hops aren't intense enough to build power, and the upper body doesn't do any work. It has nothing to do with the original exercise, the pull-up.

There are much better options. Can't do pull-ups or banded pull-ups? Do barbell, dumbbell, or band rowing... or even inverted rows. You're at least respecting the initial spirit of the exercise.