I bought these mini cards so my 5-year old could have an easier time doing some magic tricks along with me. He really likes the cards, especially how two minis turned horizontally is exactly the vertical height of a regular card. Unfortunately, because the cards are from the same stock as regular cards (thickness), they don’t bend or flex very easily because the smaller dimensions results in having less leverage. Even for me, it’s quite difficult to do a riffle shuffle.
I’d still recommend them as a novelty, but don’t necessarily expect that they’ll be useful for smaller hands.