Dang rabbit hole.
Okay so if I'm looking for some quick energy before a workout, I eat a pack of Twizzlers - for the sugar and their magical properties. Since oils are more efficient, would it be better to guzzle a couple of tablespoons of olive oil, or are sugars absorbed in the stomach and fats in the intestines? Or do sugars, though less efficient, absorb quicker than fats due to their hydrophobic tendencies and relatively long chains?
Just because the body requires less energy to digest doesn't mean that it is the best preworkout energy source. Carbs still requires less steps to get to a usuable form. The body basically emulsifies fats in bile which takes hours. Carbs are digested via enzymes (lactase, maltase, etc) and can be absorbed in minutes. Neither are digested or absorbed effectively in the stomach. Proteins are more or less predigested in the stomach though, the acidic environment denatures the proteins.
That info is very general, there are many more factors which affect digestion/absorption of macros.