Wait, isn't it the same Garrett Motion that is
filling for bankruptcy?
Not sure how revolutionary this approach really is. Twin turbochargers, twin-scroll turbochargers, super/turbo-charger combos, all do the same thing (allowing both low-lag and high RPM power). I'm not sure if this is really that much less complex and weighs less, though. Sure, you can use un-boosted exhaust to drive the turbine as a generator, but what will happen in spirited driving where you don't have that much un-boosted time and have a lot of boost demand? I'm sure it'll work well for normal driving and for HP wars (while keeping MPG ratings low), though.
F1 cars can fine tune the setup for each specific track, it's not a luxury street cars have (on the road or on the track).