They do increase the risk/benefit ratio.
Spending $1 for a one in 200-million chance to win a million bucks is mathematically retarded.
Spending $1 for a one in 200-million chance to win a 400-million bucks is a reasonable mathematical proposition.
Either way you probably aren't going to win, but at least it's not a mathematically retarded thing to do when the jackpot is high.
It’s still $1 for an infinitesimal chance of winning. The size of the prize doesn’t increase chances of winning so the risk benefit ratio remains the same, you’re still blowing $1 on a “chance” that statistics say you will not win. How much money you’re not going to win doesn’t change the fact that you’re not going to win. It’s mathematically retarded regardless of the size of the prize because you of the strong odds against you winning, the risk side remains the same and the benefit side barely nudges from 0 because of the odds against you.