A *human* assistant can give different answers for the same inputs. At some point, we'll need to stop treating computers as instruction executors and start treating them as autonomous agents. Non-determinism isn't a bug to be fixed, it's just the reality of working with this new kind of machines, and operators of those machines need to embrace that fact, like they did for human assistants.
But sometimes you do just want the same answer each time. Not this human woo crap, where the answer depends on god knows what, but a deterministic function of some kind, reliably producing a given output for a given input according to a fixed set of rules.
Computers can do that!