Elon Musk is a highly intelligent man.

He knows humanity cannot become a Kardeshev Type I (and certainly not a Kardeshev Type II) species under a high time preference fiat monetary system. A low time preference sound money system is required.

Elon is thinking about the next 100, 500, and 1000+ years. He knows there is only one money that will enable humanity to reach its full potential both today and long after he is gone: Bitcoin.

Gold won't work as money for a spacefaring people for many obvious reasons, not least of which is the fact that gold is extremely plentiful in space. Additionally, gold failed as money for humanity when we were earthbound. Gold is extremely useful, but it is bad money compared to bitcoin.

Gold was money for humanity's low-tech epoch. Bitcoin is money for humanity's high-tech epoch. Gold is the past, fiat is an unfortunate blip in the present, and Bitcoin is the future.

Elon is one of the smartest people on the planet. He knows this. He knows Bitcoin is absolutely finite. 21M forever. He is the richest man in the world. He wants to preserve that wealth for many generations to ensure his dreams become reality long after he is gone. Gold and fiat do not allow this. But with Bitcoin, he can create time-locked vaults in cyberspace that open after specific amounts of time have passed. This ensures his companies/initiatives/descendants will always be extremely well funded, but will not be able to simply waste all his wealth as soon as he is gone.

We know both Elon and his companies own bitcoin, but lately people are wondering why he never publicly talks about it. In fact, he almost seems to deliberately avoid opportunities to talk about bitcoin... Why?

Because Elon knows this is a race, and the winners of this race will cement their economic power for generations. Elon knows that, as the man with the biggest megaphone in the world, if he comes out with a full throated endorsement of bitcoin, then the race accelerates exponentially...

Elon wants to take humanity to the stars. This is only possible with Bitcoin because Bitcoin makes long-term thinking possible on a planetary (and interplanetary) scale. Bitcoin fixes the broken incentives of the fiat system which mortgage humanity's future to fund its decadent present.

Elon is going to acquire as much bitcoin as he possibly can to ensure his vision for the future of humanity as a spacefaring species is realized.

tl;dr -- you should not be suprised if it turns out that Elon has been quietly stacking an insane amount of bitcoin.