I don't think every lottery drawing is. I mean, there's plenty of stories of winners out there, some go bankrupt, some actually make something of it. There's even some crappy reality shows about winners. That being said they absolutely use it launder.

People have mentioned the story about epstein's shell company winning one, but I'd imagine that was probably a "far and few between" scenario. Most of the money laundering comes from the "unclaimed" and "deductions" part of the lottery. Every time you win and take the cash option, a part of that is deducted as a "processing fee" it's not taxes, it's a "fee". That obviously get laundered. Then there's the billions in unclaimed winnings that's supposed to go to the education system that never sees the light of day.

That being said, I'm sure every time it gets above a billion they find ways to screw everyone over and get at least a chunk of it.

EDIT: For the record, I actually know a jackpot winner IRL. He was a winner of one of those get so much a week for life lotteries. So like I said, I'm sure there is some money laundering, but people actually do win it. Most of the laundering is on the "administrative" end of things.