1. It shows that you're resourceful. You'd be amazed how often you can substitute a pour of Coke in a recipe that calls for wine, beer, juice or vinegar.
2. It solves the sad problem of flat Coke. Surely there's a glaze waiting to happen with the dregs of that 2-liter bottle.
3. It proves your mettle as a cook. As recognizable as the flavor of Coke is, it can be as evanescent as the bubbles. A great cola-glazed ham or Coca-Cola cake really does taste like the beverage.