I'd describe it as being a mashup of voting machine development with game design. Gambling is a form of entertainment for most people who do it. When they go to a casino they vote with their dollars on which games they find entertaining. But we can't send our games directly to players, we sell to casinos. And every single one gets tested and approved by and independent regulatory board whose rules create a lot of boundaries/limits on how creative our designs can be.

And the mathematician part is exactly like being a "fun accountant" for the game. We set your fun budget and make sure the player (randomly, on average) never exceeds it.