Its simple.. energy drinks contain drugs (stimulants) that make you a bit jittery. Despite their name they do not provide much actual energy other than the sugars. You drink "energy drinks" to remain alert, you do not drink them for a source of caloric energy.
Energy bars, on the other hand, are food that your body can break down for energy. Energy bars don't contain the stimulants that energy drinks do.
Moral of the story.. if you're about to play a match or engage in any kind of activity that demands a lot of energy.. eat some food. Energy bars are food that typically contain a lot of calories that you're body can use for energy.