You should change the way you use them. They mean very different things. "Non-stop" means the plane doesn't stop anywhere between two places. "Direct" means you can fly with the same flight number between two places, with as many stops and equipment changes as they want. "Non-stops" are always "direct," but there are many "direct" flights that are far from "non-stop."

You should generally avoid "direct" flights like the plague. You earn miles as if it were a nonstop, so whereas MSP-DTW-CDG is 4490 EQMs, you'd only earn 4222 EQMs for a MSP-CDG "direct" flight with a stop in DTW. And the flight is treated as a single flight for EUA purposes, so you have a 0% chance of upgrade on MSP-DTW if you're flying MSP-CDG "direct," whereas you have a decent shot at an upgrade if it's a connecting flight.