SJS, celebrating that event in Israel is showing that it’s a special occasion.
Also, I don’t think kids have a true concept of money. They have a concept of fancy and flashy vs plain and simple.
True it’s not davka about how much one is spending. But I think it’s an important part of chinuch to make a (relatively) big matzav of important occasions and issues.
You don’t have to take the entire bar mitzva party on a cruise. That’s flashy (to say the least) and sends the wrong message.
But I believe one should mark these occasions with the budget one spends on important things so that kids SEE that it is important.