Relaxation. Stress reduction. Being able to connect with people in a way you might not be able to otherwise.

Obviously, varies dramatically from person to person.

“Obvious” is maybe not quite the word I’d use, but lower inhibition, fun and social aspects are benefits of (a reasonable use of) alcohol

(Not saying it’s a good trade off or that it’s the only or best way to achieve these things obviously)

It's easier to walk up to the woman that's been eyeing you at the party, speaking from experience.

Calories.