Why do professional astronomers often prefer the parsec over the light-year when mapping static objects?

Answer

It is derived from the parallax angle, a direct observational measurement

Astronomers favor the parsec because it is derived from parallax, a direct geometric measurement obtained via observation, rather than relying on a prior assumption about the speed of light.

Why do professional astronomers often prefer the parsec over the light-year when mapping static objects?
measurementastronomylargestunits