(I have not yet cynically said "I suppose you can see how often this gets used in the real world" but it's coming)

If this is referring to limits, while I can't think of any times I've used them in a formal-mathematics way outside of academics, I *do* use the... approach and mindset?... of limits frequently in my game design work! Eg, "As Bonus X approaches infinity, what is the expected effect on the incentives/game-state/player experience?", or "As the granularity of System X increases, what does Dynamic Y converge towards?"