The dystopian downside is significant. It is not difficult to come up with half a dozen horrific outcomes of this technology.
I recently watched an episode where there was a bit about "Don't date robots" and it had me absolutely rolling, but also hit pretty close to home in 2025
I also don't trust the current brand of tech billionaires to handle this stuff responsibly - if they aren't specifically aiming for those dystopian scenarios even.
Based on all of Musk's past behavior, he doesn't exactly strike me as a guy who would deeply care for the disabled or make it his life's mission to cure spinal cord injuries - or even to grant super powers with no strings attached to the average person.
But he does seem like the kind of person who obsesses about the "next stage of evolution of the human race"...