It sounds less like a math skills issue and more like they want kids to become familiar with credit cards at a young age. In some ways, that could be a good thing; too many college students get credit card offers and then run up huge balances, because they don't know how to handle personal debt. If little kids go bankrupt in Monopoly often enough using the credit card and calculator system, maybe it'll teach them something.

But yeah, I prefer Monopoly money when playing.