Ghostscript can be used as:

Ghostscript is a language interpreter, not a Line Printer Daemon (LPD), which manages print queues.

Ghostscript is an interpreter for PostScript and PDF, enabling it to convert these page description languages into raster images or other formats that non-PostScript printers can understand, thus allowing them to print PostScript documents.

Ghostscript's role is to enable printing on non-PostScript printers, not to 'allow correct printing' on PostScript printers which natively understand the language.

Ghosting and staircase effects are typically related to printer hardware or drivers, and Ghostscript does not primarily function as a filter to resolve these specific output anomalies.

While Ghostscript can render PostScript files for display, its most significant utility in a printing context is conversion for compatibility, not just as a viewer.