It is still advantage for the casino, the more people get drunk, the more clouded their decisions are, and most likely will go all in or bet even more because of all the alcohol in their minds, win-win situation. And if ever they got unruly or something, it's simply, they are going to be thrown out of the casinos.
There are a lot of enforcers roaming around, and don't forget the eye in the sky, they can simply tell the people downstairs to watch for someone because he is drunk. Seen this before, just for a sign that someone is under the influence already, expect the 2-3 enforcers on that guy ready to pounce him if he went over board.
Since I always plan the amount that I am ready to lose, I do not mind losing it, and therefore I can afford to drink even strong drinks, because I pay for them with my losses. However, I have not yet seen someone carried out under the arms in the casino because this person was very drunk.
Of course, houses give out free drinks for a specific purpose, but they do not do it so that you lose control of yourself, you in most cases and so give them your money. You'll just enjoy it)))