Another one in favoring of letting the engine reach operating temps before (ab)using it
Also remember that there is an excellent chance that if the coolant/water isn't up to temp, then neither is your OIL. The OIL is more important to make sure engine parts aren't starved of warm oil. The actual water temp being cool likely isn't a problem, since the coolant is used to COOL the motor, not heat it, but its temp is indicative of the overall engine temp.