This chart comes from NPR and it uses government data to chart out what the average American household is spending their money on. It’s a simple enough visualization, with the biggest bubbles illustrating the biggest percentage being spend. It’s also useful to color code the bubbles according to type of expense.
However, my gripe with bubbles being used to illustrate differences in quantity is that it becomes difficult to tell the difference. Sure the change is apparent when viewing a really large bubble next to a small one, but all the ones in the middle are pretty much the same size..give or take. I would much rather use a bar chart in this case, with the values going in ascending order because then it would really illustrate the priorities of spending correctly. Right now, with all the bubbles floating arbitrarily, we have to look for the story and the free form means that our eyes will gloss over some of the more interesting figures.