This scenario happens in basically any form of gambling with a progressive (grows over time until hit) jackpot. For instance there are literally pro video poker

This scenario happens in basically any form of gambling with a progressive (grows over time until hit) jackpot. For instance there are literally pro video poker players. For some imaginary numbers let's say there's a video poker game where you play for $1 and the house has a 2% edge against perfect play. This means each time you play (in the longrun) you lose $0.02. But now let's say there's a jackpot that you have a 1 in a million chance of hitting, that has $1 million in it. This means that your expected value from the jackpot is $1 per play. So the net result in our game is that each hand you play, you win $0.98. A skilled video poker player can get around 1000 hands per hour, so you'd be earning around $980 per hour in the longrun. Casino comps make this even more profitable. Depending on the game/casino casinos will generally comp around ~20% of their expected profit against you, and that excludes jackpots. For our imaginary $1 game with a 2% margin that means you'd also be getting $0.004 per hand back in comps. It becomes quite significant at high stakes.