I assume SpaceX does it because they figure it's a good source of revenue, and it means they can keep another thing in-house instead of relying on Anthropic or OpenAI for their AI needs.
As for why anyone else would want it: I've found it's a good model for coding, and it sometimes catches bugs that other models (especially open source models) don't always spot.
As for why anyone else would want it: I've found it's a good model for coding, and it sometimes catches bugs that other models (especially open source models) don't always spot.