I've always thought bar and bat mitzvah's were basically religious in intent. Or so my Jewish friends tell me. They are the Jewish boy or girl's first aliyah (reading of the Torah) .
The party afterwards was just a chance for the family & friends to congratulate the girl or boy and welcome his or her entrance into the Jewish community.
I've been to a fair number of bar and bat mitzvahs although I am not Jewish. Some of the parties were very nice, but, needless to say, none were quite so over the top.
The religious nature of the event appears to me to be lost when you indulge in this sort of excess.
But as several have said, it's their money and their private business what they do with it.
Her wedding is going to be pretty anti climactic!
I remember watching the Hollywood Squares or something like that, and a question was posed to one of the celebrities: "On a boy's Bar Mitzvah, what does he read from?" The response: "A cashier's check"
Just precious...