"study" and "finished composition

I think the distinction between "study" and "finished composition" has been somewhat blurred. Consider the fact that Monet painted "Impression, Sunrise" very quickly, generating the name of a whole artistic movement: Impressionism. It was hardly a finished composition in the sense that the "Old Masters" thought of it, so it was a study. Plein air painters today often follow the impressionist lead in the matter, finishing a painting in one session and on site. A study can be so attractive that it rivals or surpasses a finished work. Because of it's freshness and immediacy, it has charm.