mac & cheese – the new gragger

Today the Hebrew school where I teach held an out of the ordinary Purim celebation. There were no prizes at the carnival – instead, every booth gave out paper “mitzvah money.”  Kids took their mitzvah money and placed it in a tzedakah box representing one of 5 different charitable causes. At the end of the fair, the actual money collected at the door was divided up between the charities accordingly.
Why doesn’t every shul do this?