How hard it is to extinguish is vastly, vastly less important than ‘does it stop people safely escaping’ and ‘does it overwhelm the safety equipment’.

It is obvious that having a huge goods fire from a commercial truck that shuts down people's vehicles is dangerous; that directly leads to death and directly prevents rescue. It is obvious that having isolated, separately functioning vehicles that can drive away, and a fire from a specific, planned-for factor of an understood quantity has a comparatively low potential for causing death.