Nobody knows, but my guess: Apple is hiding a test of advanced battery fault detection and monitoring technologies that will eventually show up throughout their battery-powered products. Final Boss Lightning was the simplest, least risky way to support the power delivery and communication needs in the AVP Mark I timeframe.
Battery fault detection needs to be implemented entirely within the battery pack in order to be worthwhile. USB is more than sufficient for communicating information from a battery pack to a host system.
There's no need to speculate about complicated technology based on ancient patents when there's a simple and far more plausible explanation available: Obviously what this connector provides that Type C lacks is a secure latching mechanism, which is critical because there's no battery in the headset itself.
If I had to guess, one group came up with (reasonable) requirements for this connector to handle certain currents and voltages, be reliable, be nice-looking, and be proprietary for the purpose of not dealing with RMAs related to people connecting shitty usb-c batteries directly to the headset. And another group realized "hey, we have all kinds of documentation, test results and tooling, we can make a wider lightning cable with low risk and low cost. Sure, we are moving away from lightning but since this is internal to 2 apple products it doesn't matter."
> In an alternate timeline, this might have been USB-C, part of a world where external batteries for the headset are plentiful and don’t need Apple’s special approval (or is that spatial approval? Ha ha, just a little Vision Pro humor there)
Yeesh, maybe don’t try incorporating comedy into your writing anymore.