There are many applications that require the installation of PostScript to be able to print out PDF documents.
You will have to install it if you want to configure a virtual printer with a PDF format output.
Ghostscript has a series of services that provide:
An interpreter for PostScript language and for PDF, capable of transforming these files into various rasterized formats; visualize them on the screen and print them out with printers in which this language hasn´t been implemented.
Furthermore, Ghostscript can transform the files from PostScript language to PDF and vice versa.
If you work a lot with PDF, this is the tool you need for correctly printing your documents.