Yeah it doesn't really work in either direction. If I look at a spot its hard to tell which blobs its a part of. If I look at a blob its hard to find all the spots it contains. (imagining of course them not all being labeled) n=4 is already pushing it for venn diagrams, you should probably just have a table above that point.
https://aviz.fr/wiki/uploads/Teaching2014/bundles_infovis.pd...
https://ics.uci.edu/~kobsa/courses/ICS280/notes/papers/Rose-...
I've encountered these in the wild, so interesting to see what's generating them.