Drape means the way a fabric falls, folds and moves under its own weight.
What this changes in a garment
Fluid drape follows curves and movement; firm drape holds a clearer shape. Neither is inherently better.
How to assess the workmanship
Observe the fabric on the body, not only flat. Check whether the cut gives it enough space and whether seams interrupt the intended fall.
The practical takeaway
Drape is not a universal quality grade. The same technique or feature can be executed beautifully or poorly, and it can be appropriate in one garment but unnecessary in another.