In Python, for example, whenever I'm doing operations on lists, I need to consider every function in isolation - will this break for an empty list (zip), or will it break when given a generator (anything that traverses twice)? If I pass a callback with side effects, how will it behave differently if someone calls it twice?
In a a more rigorous ecosystem, I can instead only worry about edge cases on classes of functions/data types - In Haskell, when doing the same operations, I can generally assume that traversal functions were written with consideration for functor/foldable/traversable laws, and those laws tell me how I can safely compose or swap them out without breaking expectations around those edge cases. Higher Kinded Types let code be constrained to work strictly with those abstractions, so I mostly just need to worry about "does this typecheck" and, very rarely, "is this an unlawful traversal". With things like linear and dependent types entering this mix, library authors can communicate even more subtle expectations at compile time instead of leaving users to try to anticipate them or find them at runtime - when you do need to explicitly consider edge cases, the turnaround time on discovering them is important.