[AaronFriel]

If you think about it economically, then this move and the lower limits are really quite straightforward. Money laundering through property surely has some marginal cost. The goal of the federal government here is to reduce money laundering, because any strategy to totally eliminate it would be irrational, because if the goal is total elimination then you're ignoring all other societal costs. (See: war on drugs.)

This strategy makes it more difficult to launder large amounts of money, and that's their goal. Hypothetically, let's say that the overhead to launder a billion dollars is 20%. If this increases it to 25%, then they've effectively taken 50 million dollars out of illegal circulation. That's a heck of a lot more effective than drug busts.

For clarification, I have no idea what the overhead on money laundering is, but I can't imagine it's cheap to move vast sums of money around off the books.