He is trying to build something that is combination of all things and maybe crypto could be at the center of it, like as a payment thing. The reason why he changed the name of twitter to X is the same reason. He is not secretly doing this neither, he is actually openly talking about how he wants to build one thing to hold all the things he has and twitter was the start of building that thing. One day when he has what he wants, he wants to be beyond government entity, someone who is not really in one nation like he is in the USA right now, but someone who holds enough power and information that he wants to be beyond ruling. Crypto could be a good way into that probably.