This one is a little bit different since there are actually still two (well three systems here: 48V, 12V, and the ICE). These systems have existed for quite so

This one is a little bit different since there are actually still two (well three systems here: 48V, 12V, and the ICE). These systems have existed for quite some time, since it was a lot easier to use high voltage rated components for all of the 48V high power stuff (e-turbochargers, e-hybrid-compressor-whatevers, other motor driven stuff) but keep just a single downconverter to 12V for everything else. The problem is that most digital electronics expect something like 1-5V to operate, including most controllers, processors, sensors etc, and typically this conversion is done at the module level in a distributed way. Going from 12V to 1V isn't really a problem (or 24V ish for that matter, which is what they use in notebooks), and 20V and 30V class semiconductors are easy to find and have desirable performance characteristics. Going from 48V at every module to 12V as an intermediate bus, usually requires a transformer because otherwise you'd be switching the current on for a very short time per cycle (duty cycle proportionate to voltage ratio), and this has implications for efficiency and component sizing. So I'd think this is quite a huge change compared to the old mild hybrid systems