What is use of alcohol?

Answer 1

it gives u random events: girls contact, johns, cougars, energy or excitation surge on the positive side, falling over  (hurts health or energy) on the negative (which wont happen if u re accustomed to ur drunkenness)

also it will make ur dates find u slightly more attractive ( remember this isnt real life)

Answer 2

I found it great to be drunk very often. When the random even for girl contacts come up the girl is random. So you have a chance to get top girls. I had 3 divine girls by level 17 and only been playing 2 days.