Never read about the suit aspect, but what I've read that there's a certain weight correlation between the box and the competition squat. The exact opposite of the trap bar lift.
Anyway, how do you know about this kid's particular squat? What are you basing it on?
I admit that I'm guessing here somewhat, but the guess is based seeing a lot over the years.
I'm assuming the kid box squats with a wider stance than he would do a "normal" squat. And hitting real depth on a box takes a lot of practise for most. Has this kid spent years box squatting and training his technique to hit a below parallel wide-stance box squat? Unlikely for a soccer player.
Yes, the box squat would be lower if one were doing an Olympic style squat, and deloading the quads before powering back up, but that's not how most of these kid "athletes" do it. More like bouncing back up.
The Westsiders mostly lift in feds where they wide stance squat to a shallower depth than in the IPF for example. The box squat isn't that popular in the IPF for a reason.
I'm guessing the squat here looks something like this. Slightly above parallel and "touch and go" technique. For someone who isn't a very experienced lifter, say a young soccer player, it boosts the loads you can use.
Or worse, like this. Double your loads.