they don't have to spend the money to make a parking lot in the first place.
Opportunity for fined parking spaces outside of bars? You know, the fed will sap money from anywhere ;)
Fitness. Someone might actually WALK to the bar.
None of their customers have to worry about driving home.
If their customers don't have to drive home, they spend more money on alcohol and get plastered. Not only this, but they generally make a deal with a taxi service so that they can take those drunk and without rides home. More money in their pockets.
Welcome to capitalism.
Less chance of fender benders in the lot or the possability of a patron coming in being hit by someone leaving. Which I believe will also affect their insurance rates if they have to insure the establishments parking lot. IDK if it's true everywhere, but if they have a parking lot where patrons park, they become liable if the patron is too drunk to drive and they don't take the keys away. It is not unusual for someone drunk to leave a bar, pull out of the lot, get into an accident that they sustain injuries from and turn around and sue the bar for their own actions. And they do win those cases.
From someone who doesnt drink, and regularly plays guitar and sings at bars, this would be a huge inconvenience. You cannot always make rules that punish the majority of people just because there are people who are iresponsible. That is called a nanny state, and it is counter productive. :(