One very good reason for using a hand drilling tool (one without gearing) is when you drill in hardwoods and you want the hole wall to be wood rather than charcoal. This is a very important thing when drilling up the holes for pins in old pianos, if the hole walls burn during the drilling then the piano will not keep tune.<p>By using a hand tool you are purposefully limiting your speed (you may still need to stop in between to let the wood cool).<p>Hand drilling tools still have their place, the above is just one example of many like it. But for most purposes a motorized tool (electricity, air, gasoline) is more convenient and a lot faster.