Because it's another tool to move money on books and make it seem that spaceX and or xAi look good to investors when needed. That would be my guess.

Pre-IPO price padding. xAI is going nowhere but at least for now it has some value. Move it under SpaceX, bump up SpaceX’s valuation and therefore it’s opening IPO price. Then kill xAI and write it off.

These are no longer tech companies, to they are financial, and power, instruments of the billionaire class