Some Reasons for separate :
Limit Access (eg PG-13

) needed
Custom columns are different (types or allowed values)
{Wider is slower

Lean, mean, (in)columns machine}
But since Import only creates (populates) a basic metadata
Import to an
Intake Library and plan on
moving (sorting to which) them to another one later using "Copy to Library" (on the context menu). This is quick and painless