Its their domain!
The whole scene is geared towards woman. Everything from the decor to the music. Club owners know that the more women they get in there the more men are going to pitch up trying to take them home. They all plow hundreds into the bar and entrance fees in an aim to meet women. Women get dressed up and go out with for a night of attention whoring while hanging out with their friends. They are also great places to help increase their own social status, which is why the go to the newer more trendy places. They get the ego boost with men hitting on them. Its a cheap night out for the better looking ones.
You are generally on a hiding to nothing unless you are going for the right reasons. Go to have a good time with your friends mostly. They can also be decent places to take women you are already ****ing. You dont have to talk to them too much because they are dancing with the other girls and creaming themselves with all the attention the other men are giving them while you can drink a few beers with your friends. Then you get to take the drunk, horny tart home and pile drive her. The hangover ensures an early retreat the next morning. Along with the "hangover guilt syndrome" a lot of women seem to suffer from.
Consider what you know and understand about women and then look at what nightclubs/bars represent. I cant think of a better place for attention *****s to be. Its like ****ing Mecca to them. They are good places to meet women if you are good looking, in shape or obviously loaded. If you are with the right people it also adds social proof which helps generate some interest.
Also understand that women rarely get picked up from clubs and bars, especially if they are in large groups. The last thing she needs is for her friends to think she is a slut. Not to mention the jealous women around her who will either try to sabotage your efforts there and then or pass comment about you being a loser/she can do better after she brags about you asking for her number. Why do you think so many women you meet at clubs tend to flake? Chances are that although you had her approval you did not have her friends.
All in all, I used to go there with my mates to get smashed. Sometimes you get lucky, sometimes you dont. It was just a couple of beers with the boys anyway and things got out of hand
No pressure, good times.