How can a graph of data be more informative than a table of the same graph?
A graph does one thing that a data table doesn't do, which is
allow a visual representation of the data to be created. This would
allow you to see, for example, that a series of data points rises
in a straight line far more easily than a bunch of numbers in a
table would. Additionally, graphs are good for comparing data, say
volumes or masses for example, so that you can see how one value
compares to another.
All in all, it allows you to see all the data points at once,
compared to each other, so that you can draw conclusions about the
data as a whole.