If you were in a cold climate, pulling the hand throttle warmed the engine up while you went back in the house and warmed up.
Isn't that the function of the choke and fast idle?
Obviously you have never driven a car with a manual choke and a manual throttle in a cold climate. You choked the car to get it started and then started opening the choke and pulling the throttle to keep the engine rpm up. Trying to keep the engine speed up with only the choke results in overchoking the engine as it warms up.
