I can give an example of the type of postprocessing that can be done in DPP. It is all achieved using the editing window, and mostly on the Histogram but also in other parameters. In the following pic, I made a few changes to levels using the histogram, plus did a small increase in saturation, plus a little sharpening:

And this is what the histogram and other parameters look like in the editing window:

There are many faults that show up in a photograph that can be corrected independently of the "look" of the coin, such as low contrast, sharpness, etc, but only you can ensure the edits are consistent with the correct "look".
Edited to add: I'll call this post "Tip of the day #13"