In many cities like Los Angeles public transportation is either non-existant or extremely poor, the most common scenario is that someone goes to work and is invited to go have a drink with the office gang after hours. It's not realistic for them to drive an hour home in rush hour traffic and then take Uber back to meet everyone as they'll already be gone. Instead they go have a drink, start thinking, "Geez, I probably should get Uber but then I'm going to have to get Uber in the morning to get to work and then I have to get my car from the parking lot at the bar. I guess I'm not really that drunk I can probably make it home okay."