Divekicks are rush down tools. They hit high and must be blocked standing, but depending upon the game you can sometimes initiate them very early in a jump making them a quick overhead that often leads to a combo. The fact that they just be blocked standing often turns every jump you make towards your opponent a possible mixup. If I whiff the dive and land, depending upon the recovery I might be able to throw out a low attack and catch you while you were blocking high.