It is a traditional game, known internationally, in which blindfolded children strike in turn, until they break a suspended container with a stick. It is usually full of sweets and candies.
Because it is a very well known and very colorful and very funny decoration that gives a touch of magic and reminds me of birthday parties when I was a child.
For all the reasons listed above and because all children know it, they have had one or would like one. It hangs like a real piñata, opens in half and the brick "candy" comes out just like a real piñata.