why do some sportsbooks let you combine sports and casino bets.

i’ve noticed a few places letting you mix sports parlays with casino spins or even live dealer bets in one slip, and i’m trying to get my head around who actually benefits most from that. like i get it makes sense for the house since more action in different verticals probably means higher margins for them, but for bettors it kinda feels like it’s just spreading risk more thinly instead of really increasing value.

does anyone actually play these combo slips on purpose or is it more just to chase the promos? i keep thinking about opportunity cost and if i’m throwing away edge by mixing games where the odds and variance are so different. feels weird hedging a soccer pick with a blackjack hand.