Keeping the parent vessel intact preserves the crew's safest refuge. At sea, abandoning a still-viable ship for lifeboats can expose survivors to more danger, and dependence on the main hull would be greater in space. Even a large spacecraft capable of rapid manoeuvre need not accept the close-combat risks that cheaper parasite craft can bear. The carrier can retain its command systems and people at a distance while the smaller vehicles make the dangerous approaches.
Notable Point · 2:48:29-2:52:59
Keep the fight away from the crew's safest refuge
The parent spacecraft carries the people and command systems that smaller combat craft are meant to protect.