As I'm not trying to set any world records nor do excessively high-risk activities in the pursuit of fitness, I think they are unnecessary.
I'm personally in pursuit of high-return, lower-risk exercises. I do think there is such a thing as "enough" strength for the things I want to do and the things I will unlikely encounter.
If someone can do jumping pistols, especially even moving further along Coach Sommers' progressions (pistol jumps to a box, pistol jumps for forward distance), I'd absolutely say that was enough strength.
Mainly I don't like the relatively large load spread over a relatively small area in jump squats, only to be combined with ballistic, gravity-fed movements.
Sure I think it works well in the short run to build explosiveness. I'm not in it for the short run, neither is my advice to others, so I would avoid it.
That being said, I think jumping squats or jumping pistols with weight added in the form of a well-fitting vest is much safer and smarter. Heck, just do Tabata squats with added weight, only going up in weight once 20 reps every round is reached. The X-Vest has a vest that goes up to 80#. That seems like enough to me.