Don't fall into the trap of assuming the circumstances you saw, are the ones you'll get.
I believe the original point was "if a situation presents itself in which you DO have the opportunity - I e. The vehicle is momentarily stopped in front of you - is the only thing preventing you from making that shot fixed by buying different ammo?"
Nobody is saying "in this instance, the best thing to do would have been to shoot at that vehicle from whatever vantage point."
But if you've ever seen vehicles lose control you have probably seen this happen: it hits something, like a wall, pillar, or parked car, and stays basically stationary for ten seconds while the driver figures out what he's stuck on and how to pull away.
Given that vehicle attacks are increasing...if you're choosing ammo, why wouldn't you choose ammo that would let you make that shot?