The point, for most people, of playing these lotteries isn't that they expect to win, though that wouldn't be unwelcome. It's more the creation of hope- from the time they purchase that ticket until the time they find out it's a loser, they can hope that they won't have to go to a job hate ever again. They won't be saddled with debts that they've forgotten the cause of, or a wife and children they've long since grown distant towards, or the forced interaction between acquaintances who feel like they need to grow closer.
Lotteries allow for the hope to live whatever life you'd like, and for most people, that's worth a couple bucks a week.