This type of handle is used to prevent slippage, accommodate a battery, and to provide you with better overall balance of the drill. If your using the drill for heavy duty drilling such as driving large screws you would be better off with a pistol grip drill which allows you to put pressure higher up and almost directly behind the drill. A cordless drill generally has an adjustable clutch where an electric does not. The clutch on the cordless drill will disengage the drive shaft whenever a preset resistance is reached, so not to strip out the screw or overdrive it. The motor will keep running, but the screwdriver bit will not be turning.
Drills are also available with variable clutch settings .
The better cordless drills have at least 24 settings enabling you to really fine tune the power delivered. Settings with lower numbers are for smaller screws and the higher number settings are for the larger screws. There are many different models of cordless drills out on the market today making it very easy to purchase more tool then you really need. You should purchase a drill based on what jobs you will be using the cordless drill for. A general guide to follow is for light maintenance and repair jobs, usually a 6V to 7.2V will work out very well.