As modern driver head sizes have increased and tees have become longer, the golf ball starts higher off the ground than ever before. To hit the ball in the sweet spot consistently, the clubhead must come well off the ground at impact. A traditional start with the club on the ground at address and the ball in the center of the face doesn't allow for the extra tee height and can easily cause poor contact toward the heel. There are two ways to combat this; if you like to rest the clubhead on the ground at address, place the ball in line with the toe of the club. If you hover the clubhead off the ground at address, position the ball in the middle of the clubhead.
Today's huge titanium driver heads require a much higher tee height To optimize launch angle and distance.