The gobsmacking caches of A-series parts allow Apple to keep the beast fed, leading to fewer stalls and more efficient use of CPU time. This advantage redounds to better battery life because well-fed CPUs can retire work faster, returning to lower-power states sooner. That it has taken this long for even the top end of the Android ecosystem to begin to respond is a scandal.
I think he is making the argument that the levels of cash mean the CPU gets worked on much faster By avoiding the need to wait during round trips in a high power state.