The whales usually don't try these promos as they have enough funds to wager normally on the roobet slots and other games and enjoy their way this way but you see majority is small gambler and they want such competition and promotion as extra reward that binds them to the casino.
With whales, participating in wagering contest and win it is good enough for them. They can use bot to dice and increase their wagering amount in the contest. In the end, if they are smart and experience, they will win wagering contest but still be able to maintain their initial capital.
Promo is not what whales mainly look at because in most of promotion campaigns, reward is not attractive enough for whales.
Exactly, you always need to keep the people motivated to come back to your site so promotions play a vital role. And have a variety of promotions so you keep everybody happy (casino and sports players). Besides that, costumer service also plays a huge role. If you don't care about the players and have a bad support, you will start loosing players when there are issues.
Promotion play its role as noise-making and attraction to potential new users. Promotion is important to turn guests to real users. I don't say promotion does not give current users opportunity to join but it is not main purpose of promotion.
If a promotion is good, it will be spread by current users to their friends, relatives and communities in which they participate. It is like a small gift in order to attract more users and more income for a casino.