1) teaches new clients how to control the squat descent and keep tension in the quads. I think the eccentric portion of the squat can be somewhat overlooked, so by having to pause you must think much more about the descent and not just drop down and get back up. When I managed to control the descent myself I found that translated into a stronger and controlled squat and bigger legs also
2) I get way more quad activation, even when squatting work way less weight than my heavier squats
3) if you're squatting frequently, then alternating this exercise with standard squats means you can use lighter weights to take a bit more stress off lower back and joints while still getting great quad activation
4) it has cross over benefits to your standard squats as it will help your squatting strength and drive from the bottom
5) by shifting the weight to the outside of feet, then pushing your feet through the floor you'll feel your outersweep working very hard
Give them a try.....