A Barcode Report is a full-size sheet displaying your barcode and the settings used to create it. You can print it out (or on a Mac, save it directly as a PDF file).
It's simply used for reference and diagnostics. Many of our design users print this out to give to their clients as a formal presentation of the barcode that has been created for them, and many pro users deliver this as part of their final deliverable package alongside their barcode.
It's an excellent way to print off a fully valid, scannable barcode, along with everything you did to create it.