After having worked with a lot of data visualization I came to the conclusion that the purpose visualizing most data is to show proportion, trend or significance not details.<p>I.e. it only has value if it clearly visualizes the point trying to be made. Otherwise you might as well show it on a list or it might come up as an alert.<p>The challenge is not to be able to read and understand graphs but to know what to do with them. This is why most dashboards are purely made to make the product look sexy not to actually provide any valuable insights.