Why does carbohydrates play a leading role in the processes of energy conversion in organisms

Why does carbohydrates play a leading role in the processes of energy conversion in organisms, although when 1 g of fat is broken down, twice as much energy is released?

The body can get energy from carbohydrates (normal), as well as fats and proteins (very rarely).

However, these compounds have different functions.

Fats (lipids) are consumed mainly for the construction of cell membranes, and are also necessary for the biosynthesis of certain hormones. However, their breakdown can occur if insufficient carbohydrates are supplied to the body.

Proteins are broken down into amino acids, from which other proteins necessary for the body are then synthesized. They have many unique functions, such as enzymes.

And only carbohydrates have the main function of providing cells with energy.