New XiOne-SC(B) boxes vs old X1 boxes

I currently have:  Primary TV Box    PXO13ANM

                              2nd        "     "       x1   XG1v4-A

                              3rd         "     "       x1   XiD-C

Received 3 new boxes   XiOne-SC(B)

I want to continue connecting the boxes with coax, not internet.

Do the new boxes provide that much "enhanced performance, faster load times" vs my old equipment?  If it is a significant improvement I want to upgrade using coax not internet if possible.  Can I connect the 3 new boxes via a MoCa adapter using my existing coax?

Will the 3 new boxes work without my Primary TV Box?  I have ComCast Internet, do not have a ComCast Modem.