1.  No drinks means it's a cheaper meal.  It's not that I'm that cheap (though I am cheap to some extent).  It's just that I have trouble spending more than I need to on some cheap fluids.  I could bring a whole bottle of soda to a restaurant and quench the thirst of 5 people for the same price I'd be charged for a single drink.  And that's just soda; it's even worse when it comes to alcohol. 

2.  It's ready when you get there.  There's no need for reservations, waiting for a table, waiting to order food, waiting for it to get there, or waiting for the check.  You just call ahead and show up when it's ready. 

3.  There's no tipping when there's no service.  This is the best part.  Again, it's not that I'm that cheap.  It's just that I don't feel the need to pay somebody a percentage of the price of my food just because they brought it to me.  I'd be more than willing to take my own order, march back to the chef, ask for my food the way I like it, and then pick it up when it's done.  Heck, I'd even be willing to bring my dirty dishes back to the kitchen.