Those are extremely interesting. Personally, out of polite interest I would also like to see the traditional dances of the viewers' cultures.

As regards the Peruvian dancers, I can think of some festivals in England where they would be a lot more welcome than the amplified pan-pipe merchants that occasionally intrude.

The American movie is described as "probably East Coast USA, almost certainly pre WWII, perhaps as early as the 1920s." Well, the CDSS was founded in 1915, inspired by Sharp's work, so maybe we are seeing the fruits of the enthusiasm which fired the first members. Technical details about the film might give a few clues: safety film (better for archiving than inflammable nitrate), and the 16mm format, were introduced in the 1920s for example.