I'd say B is nearly always the better choice, because halting is a known state it's almost always possible to recover from, and going into unknown state may cause you to get hacked or to damage your peripherals. But if we were operating, say, a Mars rover, and shutting down meant we would never be able to boot again, then it'd be better take kernel A and attempt to recover from whatever state we find ourselves in. That's pretty exotic, however.
In the case of an unanticipated error in a software component, we always need input from an external source to correct ourselves. When you're the kernel, that generally means either a human being or a hypervisor has to correct you; better to do so from a halted state than an entirely unknown one. Trying to muddle through despite is super dangerous, and makes your software component into lava in the case of a fault.
That you view it as exotic is partly a lack of imagination on your part; with a little more effort it's possible to identify similar use cases that are much closer to home than Mars.
But that doesn't really matter. What matters is that the Linux kernel needs to support both options, because it's just one component in a larger system and that context outside the kernel is what determines which option is correct for that system.
If you feel there are some that would add to this conversation, feel free to share them.