The problem is, marking out space for a watch party, although beneficial for those interested, does nothing but piss off those NOT interested. I would guess if someone is traveling to the US for the WC, they're not going to go to a theme park for a watch party (that will cost $100+, food and drink not included), they're going to go to the game. If their team isn't playing, THEN they go to the theme park.
Based on my understanding of crowd levels, they DON'T need an "extra draw" to get people in the gates.