A typical book averages around 300 words a page, whereas a comic has generally six pictures per page. Applying the adage "a picture's worth a thousand words," that makes six thousand words per page.
Infographics have been used in cartooning for quite a long time because of the power of images. Even if they're not literally worth a thousand words, presenting data and information with pictures can range from simple to complex; even so, not all visual presentations are equally effective.
Take a conventional periodic table, for example. When we look at one, we see an organized table annotated with various numbers, but without understanding the underlying principle--electrons surrounding atomic nuclei filling shells of either two or eight electrons--we abjectly fail to grasp the ideas it organizes.
Even when expressing abstract concepts Gonick uses an illustration of topology. Cartoonists use people because the human eye sees people. Seeing people has the effect of humanizing even the most complex subjects, making them accessible.
Nuance and small detail in visual presentation make huge differences to the viewer in how the information presented is processed visually and understood. Simple isn't always better, though. While a degree of abstraction is a good thing, over-abstraction can be confusing or simply fail to convey the depth of the information.