…le. Certain user interface elements are particularly janky, especially when pushed to their limits. If designers know which elements cause jank, and more importantly, the limitations of those elements, they can create designs that are less likely to result in janky apps.
So why do we put all this data on the page anyway? Answer: so people can do shit with it — make decisions, investigate, predict the future, whatever. The point is, your users aren't marveling at the pretty colors you've selected, they are trying to do their jobs.