The report automation section is not specific to Nessus; in general, the multiple Vulnerability Assessment tools available in the market and their older versions don't support the generation of reports in the Microsoft Excel or PDF formats. In order to make the most out of those autogenerated reports and to conform them with organizations' preferred reporting formats, mostly Excel or Word, scripts can be written to convert those default reports to generate reports for our own needs.

One other need for Nessus reports' automation is that while you integrate Nessus reports using different tools, such as Archer and Agiliance, which are governance risk and compliance tools; the security information and event management tool; or any other tools available in your organization using which you want Nessus to generate Vulnerability Assessment results. In these cases, for integration, every tool has certain prerequisite formats for reports. Most tools accept CSV formats. In order to convert reports to the desired formats, I recommend writing scripts.