If I remember correclty from my aviation days, the flaps are used to increase the angle of attack and therefore reduce the stall speed and increase lift. This allows the aircraft to climb quicker. Also, airplanes fly better in colder crisp days (like today) and need less room to take off. Since the runways in MSP are long already, it probably wasnt a necessity (I bet a Saab can always take off from MSP without flap with that much room).

You can also take weight into consideration. A lighter aircraft needs less flaps to take off.

Gary