"Roberta" is fairly typical of the movies set in Astairerogersland (as one author called their world). What is atypical is that their roles are not the main ones. Fred and Ginger supply the vehicle to get the actual leads, Randolph Scott and Irene Dunne, together; their own romance is more of a subplot. They do, of course, sing and dance, most excellently....
Dunne provides the showstopper number, with an excellent rendition of "Smoke Gets In Your Eyes" performed to balalaikas. She also supposedly supplies many of the costume designs for the characters in the plot (which were actually created by Bernard Newman, and were wonderful). Watch for a young Lucille Ball in a frothy, feathered evening gown in the final fashion-show sequence.