If you’re also not familiar with these, they’re little circular pillows made of edible paper (similar in size and texture to communion wafers, I’ve been told) filled with a sweet/sour crystal powder. It was kind of fun playing with the different ways to eat these. If you shake them, they rattle, and if you pop them in your mouth, you can let the paper melt on your tongue until the sour crystals spill out of them. You can also bite off one end and pour the crystals into your mouth. I can definitely see the appeal for kids of all ages. That said, flavorwise, these are not exactly my cup of tea, but then, I didn’t grow up eating them. I can imagine that if these are a part of your childscape, this would be a fun addition to your candy repertoire.
I haven’t checked any brands of this type of candy beyond Delhaize’s store brand, so if you’re looking elsewhere, do double check the ingredients. Especially keep an eye out for E120, or carmine that might be used as a colorant in other products. Delhaize uses only plant-based colorants in this particular product.