Good point.

OP, did you mean "non-stop?"

"Direct" in airline parlance means that you can have an intermediate stop, including possibly a change in planes... as long as both flights have the same flight number.

There are a number of downsides to direct flights. They can cost more, you get less FF credit, and if there is a change in planes, you can miss your connection. Yes, your connecting flight DL xyx can depart while you are arriving on DL xyz. And, you do not get upgraded on any segment unless you are upgraded on both segments of a direct flight.

Direct flights are a marketing trick that only benefits the airline.