[Symbiote]

I've seen maps showing population rather than area in several places in recent British elections.

Here's a recent example: https://odileeds.org/projects/hexmaps/constituencies/

And here, where the first graphic is from 1895 and uses this approach: https://www.geog.ox.ac.uk/research/transformations/gis/paper... ... and Figure 31 (p28) has an American example.