The fact that it doesn't burn any of our economy at all?Again, what part of two front war that's liable to escalate indicates we can afford to burn our already damaged economy and important actions away right now?
My plan lets the full +4 econ from the Baby Boom stay along with a +1 econ next turn from the settlement.
Also the provinces can't spend all 3 actions on the megaproject so they'll likely do some Expand Econ, giving us even more boost.