confusing difference when when adding vs importing systems from a different test session

In System Management as a vendor user:

- If I select "Add an existing system in a session", I get an exact copy of the selected system (green arrow in the attached screenshot)

- If I select "Import systems from another testing session", I also get a copy, but I am forbidden from editing the system name to make it the same as the previous testing session. (red arrow in the attached screenshot)

Why? What is the use case for choosing one of these methods vs the other??