So now that I've posted my uninformed opinion, I thought it was time to watch the actual video
It's not as it seems; he does explain the "clickbait" by the end of the video. I won't spoil the suspense
Interestingly, with the new LeafSpy Pro battery pairing facility that he was beta testing, no CANbridge is actually required! [ Edit: but see Mux's replay next message, over the page. ] The new BMS takes over, and understands the new battery. Some strange things happen however, such as the estimated range (guess-o-meter) alternating between current and maximum range. The same thing happens on some Leafspy pages. I'm not certain that I believe that the two figures are current and maximum estimates; perhaps more details will emerge later. The URL below cuts to the part showing the alternating range estimates (then press play or whatever to watch normally):
The ability to charge to 80% is also gone, (or at least it stops working), as the support for this is apparently in the BMS, which gets swapped out along with the battery. So the CAN bridge can be used just for that feature.
2012 Leaf with new battery May 2019. New to me June 2019.