It won’t work–it won’t do any more than make some possible incremental engineering improvements to the tech that other people have already invented.
Sure, some of the engineering is cool. They’ve taken stuff other people have done (often decades ago) and made it smaller and a bit better. They haven’t done anything really novel.
But the claims they’re making are absolutely preposterous. Musk said “we’re confident it is possible to restore full body functionality to someone who has a severed spinal cord”. Uhhh, a brain implant can’t do that DUH.
He also said “Even if someone has never had vision ever, like they were born blind, we believe we can still restore vision”. I don’t expect anyone here to understand this, but that is impossible, for all intents and purposes. MAYBE some very crude edge detection and blob visualization would be possible, IF the implant was installed at a very young age, but that’s not what people think of when they hear “restore vision” to the blind.
The list of conditions he’s claimed can be treated by this is silly. He’s put an electrode array in the primary motor cortex and produced movement. That was done decades ago. The chasm between that and all the stuff he’s promising is just absolutely ridiculous and totally hand-wavey. Real neuroscientists know that he’s mostly full of BS.