Casinos will take into account carefully why they give promotional bonuses to their users, I think when they spend a large budget for a bonus it is still profitable for them, and I never thought they would suffer losses because of spending a budget for bonuses. It may be true that they will lose profits, but if it is in their best interest in the long run, why not do it? after all this kind of thing is something that increases the number of their users at the beginning they are still pioneering to become a big and trusted casino.
Bonus is not meant to become profitable to the casino. They are gambling on the marketing hoping that they will attract more users but that doesn’t that a player conversion is guaranteed.
In this case. Duelbits bonus is a pure cashback without any wagering requirements. A user can take home hard cash without risking huge money and by just doing the minimum requirements to become eligible. Bonus is the way of casino to return part of their profit to the player. Which means they are really losing profit in here but they are expecting a return by means of player being loyal to the casino to contribute more profit from house edge.