Graphs are used to study the structure of data and to report the output of the analysis visually.
As a tool of Robust Analysis, graphs are very useful and powerful.
In Data Science, graphical approach is one of the Data Literacy.
Graphs are made in the limited area. So "Selection of the varaiances of X axis and Y axis" and "Range of each axis" is important to make good graphs.
Check points are "Outside of the ranges" and "Are there another important variance?".