The Library is not just about "pretty pictures" for renders. Every object contains and Interactive Schedules data. If your library is broken, your door schedule shows question marks. If your library is outdated, your energy evaluation model is wrong.
Modern libraries are moving away from proprietary property names toward universal standards. Your Archicad library is now writing data that is readable by Revit, Vectorworks, and Civil 3D without translation. archicad library
Do not modify the default Graphisoft library. When you update Archicad, the default library gets overwritten, erasing your changes. The Library is not just about "pretty pictures" for renders