Generally, the monorail is a bad deal if you're traveling with a group. You could take a taxi anywhere the monorail goes for less than the price of two monorail tickets. You also won't have to walk all the way through the casino to get to the station.

Why they didn't bring the monorail to the airport in the beginning is a mystery to me. It would probably be worth it to take it and avoid the taxi queue (assuming you're going to a hotel directly adjacent to the monorail).