Actually that is because by default you must have your scene scale set in cm, which is “0.01” meters. So it is a way to import cad consistently at the same “relative” size, regardless of the units. Omniverse does not support imperial measurements, so feet and inches. We only support metric, and the default value is 0.01m or 1cm.
These two numbers are related. If you make this default unit “1” then the program works in “meters”. Anything less than “1” it falls to cm.
Here is a GREAT VIDEO explaining the whole process using our “Metrics” system. This will help answer your questions. Metrics Assembler — Omniverse Extensions latest documentation (nvidia.com)