Not necessarily. In the event that your lens does hunt, if you set the limiter to 3m-∞, and your subject is more than 3m away, the lens will save time hunting. However, if your subjects are going to be closer than 3m, then there's no use limiting it.
Setting to 3m-inf will have faster focusing speed as long as you are more than 3 meters from your subject. If subject is closer, use 1.2m-inf. It's just a distance switch that avoids the lens trying to focus close up if you already know your subject is far away.