My intention with this is to make sure that if someone were to desolder the flash chip and reprogram it, they could completely own the device without the device or SoC manufacturer having a say in it or a way to prevent or detect it.
Example: I’m perfectly fine with my Touch ID sensor having a crypto-paired link to my SOC so that someone can’t swap in a malware-sensor at a border checkpoint; I also don’t want my device (or websites) to be able to discriminate against me installing my own homemade sensor. What that looks like in practice is close to what we have now, but not quite there yet — and is definitely not ‘no crypto-pairing at all’, as a ban on key material would enforce.