That'll make scanning for malware more complicated...
The issue of Yet-Another-Hidden-Processor is *already* an issue with some USB sticks (reportedly) using cheaper ARM processors to act as the USB-to-Flash interface. Those sticks thus being hackable to hide the clever malware in the USB stick's processor, and *not* on display in the GBs of flash.
All together now, say it with me: "We're all gonna die." (IT Security-wise)
Precisely hopeless, until somebody somewhere does something with signatures and Block Chain and magic, and every last embedded processor in the world needs to be Internet-authorized every few milliseconds, etc. etc. etc. ... In other words, precisely hopeless.