The holder doesn't look as clean as using badge magic or sewing but I can see it's purpose.
We are trying to reuse and recycle our uniforms as much as possible and the one challenge in handing down the shirts, is the damage the 4 patches leaves on the shirt either sewn on or by using badge magic. He can learn to sew the 4 other patches, no doubt it's a useful skill. I would caution that if your kid is the only one with the holder he may feel awkward or maybe he'll start a new trend, you never know, so be sure to check with him before you buy it. I know quite a few parents around here who might really like the holder idea. As the Quartermaster, I am thinking of letting parents know it's available for those who are interested.
To the parent who was given a hard time for using velcro,: We are an Army family and I would like to note that my husband's uniform has all velcro patches. Nobody teases him about his uniform or his velcro patches. It allows us to pull off the patches for each wash and keeps everything looking sharp through multiple washes and years of wear.