When assigning a material, the description is displayed as highlighted below.
Material has description
When choosing a library there is no description present to describe the library.
Library (Generic) has no description
When selecting an instance, there is no description of the instance shown.
Instance has no description
My suggestion is when choosing a library and an instance, the Description parameter be displayed to indicate what the name of the respective library and instance is highlighted. Something similar to the Material placement dialog would be very helpful.