The players win when Spike is working the casino floor, which means that the house is losing money. So why did they keep him employed?
Answer: Spike is the Resort's dance instructor, not a dealer. He is not working the casino as much as the other employees, and the few times he does, he is usually doing it as a favor to them. And yet the simple fact that he might be there brings hordes of people to gamble.
If Twilight was taking orders from Impossibly Rich, why did she try making amends with Spike throughout the story?
Anything less than her usual behavior would be suspicious.
Also, this means that Impossibly can approach people for recruitment into her gang. Desperate people will do anything.