101 in E&E / mechatronic engineering is to never have single point of failure and should be fault-tolerant and fail safe even if it fails.

For this case it seems that the system is designed to failsafe but not fail-operational. I guess BYD is more conservative and will shutdown once the system detect a fault even if it's a minor one.

They can improve their system by making it fail gracefully. At least keep the electric power steering, brake booster and ESP working until it stops completely.