When we intend to inform, which is the essential purpose of data visualization, we can’t select the form of the display arbitrarily: the form must be selected to support the intended function…
the primary goal of any data visualization is to inform, and that it should be carefully and knowledgably designed to support this goal based on the principles that we’ve learned through years of research about graphical perception. We should stick with what works. When we stray from these principles, we should do so because the situation demands it, which is at times the case. If we never learn the principles and understand how and why they work, we’ll never know when it’s appropriate to stray.