When the key relationship being visualised is not spatial, maps can leave readers with too much information to scan and memorise.
Smith, Alan. How Charts Work (p. 205). Pearson Education. Kindle Edition.
Maps are not the solution to every visualisation problem involving geographical data. They should be used “only when specific locations or geographical patterns in data are more important to the reader than anything else”.
Smith, Alan. How Charts Work (p. 207). Pearson Education. Kindle Edition.