You are right on that point, most of those influencers are not actually gamblers, they are just used and paid by gambling or casino owners because of their millions of followers and their ability to influence most people to gamble their followers
Personally, I consider anyone who promotes a service that he is not interested in or he didn't try it himself a cheater. He is deceiving his followers. How can you guarantee the quality of the service if you didn't test it or don't even know what it's all about!
Second, for business owners, I believe it's more profitable to advertise your service on channels which most of their followers are interested on the service you offer even if they have a small number of followers. It's not about the number of views but about the number of potential customers.