The heroine didn't fit the time period, IMHO
I really wish I could turn off the nitpicky part of myself that prevents me from just enjoying a film, but this movie had a few major anachronisms, in my opinion. For example, why is the Peppy Miller character considered a revelation of the talkies, when the spunky flapper persona she embodies is mainly associated with silents, and was certainly nothing new in the late 20's/early 30's?
In actuality, an Argentinian beauty like Bejo probably would have been cast as the "exotic" in that time period, not as the cutesy heroine. Not to say Bejo didn't perform well, or look gorgeous, and I liked her dancing, but I thought her look was way too sophisticated for the role as written. I would have toned down her Carole-Lombard-in-1936 eyebrows, for starters. (Lombard's eyebrows were a different shape in the twenties.) Bejo's whole look is very contemporary, and I could never quite believe that she lived in the movie's setting.