Despite Elon being insane, the idea of brain-computer interfaces could be really great. I'm thinking of people with disabilities or debilitating injuries. This could enable prosthetics with full dexterity that you can control. It could be life changing for some people.
I don't know if that is the first thing Elon is aiming for, but any breakthroughs in the technology that could lead to it becoming a legitimate option to improve people's lives, I think would be a good thing.
"Sorry babe, but your canthal tilt is wayyyyy off and I highly doubt your IQ is within the required 7 points of mine (15 points would be acceptable of you rated 7 or higher on the objective attractiveness rating scale)".