We'll get it fixed as soon as we can. You are right that the graph does not really provide any special insight or new information. It is just a convenient way to summarize the results of a column chromatography experiment. Just like a flow chart is a convenient way to summarize how you will carry out a project.
Elution is just a method.
It can be used in a variety of ways. It is used in the context of this experiment to remove the LDH from the column. Most of the purification has already occurred before you elute the enzyme. But the use of the special adduct in this case allows the elution step to be a purification step also. If you still feel unsure about these concepts I urge you to attend the Monday tutorial.