Then again, there's also the question of why removing EFI configuration variables would make the machine unbootable; you would think that in the absence of any explicit configuration, the firmware should just choose a sane default. That would be like making an rm -rf / also reset your BIOS settings, which is probably surprising but easily recoverable behaviour. This seem as crazy as mounting the whole flash ROM as a filesystem, so deleting it erases the firmware. The symptoms described do sound like what happens if you try to boot a motherboard with a completely blank BIOS chip (from personal experience...) --- the system will power on and just stay on, but nothing else will happen, not even a POST beep.
Edit: given that the majority of users have probably never touched BIOS/UEFI settings so that they remain at defaults, resetting them would not be noticed by them either. It's likely the advanced users, the overclockers and so forth, which will be running non-defaults.