I'd imagine this was introduce adverse failure modes like - slamming to a stop without warning within seconds on the highway if power is lost, rather than coast

I'd imagine this was introduce adverse failure modes like - slamming to a stop without warning within seconds on the highway if power is lost, rather than coasting to a halt... and then being untowwable as the car can't be put into neutral. Tesla's that lose battery are already a challenge to tow as the parking brake cannot be disengaged without power.