AFAIK Woz only really worked on Apple II and Apple /// but his Apple II disk drive controller lived on and was included in the Mac.

Ehhh, video core is basically just a (iirc multi-core/-thread) vector processor. Funnily enough, this also makes these rather cheap number crunching hard real time chips with the high-bandwidth IO (for hard-real-time) of a Pi. Notably, it's camera/display interfaces.

Could it be a protection of IP? This way program on main CPU cannot access initialization code and the user cannot learn how to do it.