Personally I’m a big fan of the Santa Clause myth. At an early age it’s hard to imagine that your parents can be wrong let alone intentionally mislead you. Learning the fact that Santa Clause doesn’t exist is an important part of developing an awareness that authority figures lie and their lies are almost always self serving.
The loss of Santa Clause is important because it destroys magical thinking. You may find it cute that when your child wishes upon a star, but you don’t want them to be vulnerable to manipulation.