Earlier quoted context omitted.
Black Mirror is fiction, a lot of it works well thanks to our suspension of disbelief. Remove cloud from the equation, replacing it with a properly safeguarded fully owned hardware located on your own premises - basically make it privacy-respecting, minimizing abuse potential, do a proper audit, and it becomes a super desirable system for people with neurological differences (or just stressed folks - attention and me…
Have you watched the Black Mirror episode in question (S1E3)? Because the point of it was the tech itself and had nothing to do with sharing or the cloud.
Also you might not realize how much the hard of hearing, deaf, and other neurodiverse ADHD types would find a memory prosthetic like that very useful unless you are in their very own shoes, for possibly years.