This is not new, it’s bee around at least a century or more and has been shown to be very effective, especially in Waldorf School settings.
Kids often have trouble controlling their body movements. Wearing a weighted vest is a effective and humane treatment. The hyper kids feel more in control and more confident wearing these vests.
My DIL is an Occupational therapist in the schools, she uses them.
I was just thinking about Cesar Milan, he recommends saddlebag type things with weights for hyper dogs.