The short duration of the pose benefits the model because they don't need to keep their poses for a long period. This also benefits the artists because it helps them concentrate on the essential elements of the pose. With this type of drawing and posing, an artist simply does not have time to draw all the details, so they learn to ignore them and concentrate instead on the important elements. Croquis is also a good method of drawing subjects which won't stand still and pose but rather keep on moving, such as animals and children. Croquis drawing can then be used as a foundation for another work of art such as a painting or may be used as a work of art itself.
The word croquis comes from French and means simply "sketch".
In fashion, the term refers to a quick sketch of a figure (typically 9 heads tall as this is the accepted proportions for fashion illustration) with a loose drawing of the clothes that are being designed. Often a large number of croquis drawings will be created for one finished look, which is fully drawn and finished.