That's not true. It sounds like you're confusing nicotine with caffeine. Nicotine is often credited with "taking the edge off" when in reality, that "edge" is a result of nicotine withdrawal.

Caffeine blocks the receptors that react to a chemical the body releases when it's tired. You're right that it doesn't give you more energy, but it does stop you from feeling by tired.

Out of all the common legal drugs (nicotine, alcohol, THC) caffeine actually provides some of the best benefits with least intrusive drawbacks.