Stump Grinding is a different process than completely removing a stump. If you have a stump in a hard area where the limbs might even be under a house, driveway or sidewalk than you are going to want to grind the stump so you don't cause any damage to those structures.
Why Grind Stumps?
Grinding stumps is necessary in many cases, especially in high traffic areas or in areas where you need to mow, walk or drive through. You want to minimize the risk of causing more damage to machinery or even breaking a bone from falling. So it's best to grind or remove them down.