This short documentary was originally meant primarily as an upbeat feature in support of a popular government program, but today it is especially interesting as a piece of history, in a number of respects. Even by itself, it would be a worthwhile look at the practical effects of the Works Progress Administration in alleviating some of the worst effects of the 1930s' economic depression. But it is probably most known today for its inclusion of the last few minutes of Orson Welles's distinctive stage version of "Macbeth", which adds an intriguing bonus to the movie.
While the documentary takes a look at the WPA's work in many different fields, it focuses specifically on the ways that African-Americans were affected by the depression and then helped by the WPA. It thus provides a look at a significant aspect of the depression that is not often considered on its own.
It's also interesting that it devotes so much of the running time to music and the performing arts. Many of the issues involved with government support of the creative arts are still debated, and in that respect, this feature might add a useful historical perspective.
The footage of the "Macbeth" finale in itself would of course make any documentary worth preserving. This is the version that the young Welles (then known mainly through radio) set in Haiti in the (then) relatively near past, with an all African-American cast. Even given the limitations inherent in a film of a stage show, it's very interesting. And the rest of the documentary is also far from without some points of interest as well.