I found Bionors without subs sounding much better, all the way through. I corrected my typo of Marty's JBL to JL."Necessary" is a philosophical question. Bass extension and power is a subjective parameter.
What is not necessary to you may be highly desirable to someone else.
David has JBLs. Marty has JL Audio Gothams.
My reply was in response to your video compatriot "wondering how many have experienced subs with strong real bass" - Rofl at real.