I’m not convinced this would apply to OpSec people who are physically unable to move any limbs.
Pro and cons of course, but..
A computer virus that can access brains is a scary thought and I'm not sure what would alleviate that concern for me.
That said, if you need this, the security side of it is a secondary concern to the very immediate quality of life improvement.
Yeah, there is a whole interesting story about the Thoratec Heartmate II bloodbpump ("artificial heart") implant and Dick Chaney. Can't be having a back door into the VPs heart implant...