Actually Elon Musk is not the only rich famous person who supports crypto more than fiat. Mark Cuban, Robert Kiyosaki, some rich politicians etc. Robert Kiyosaki said that "I'm not betting on Bitcoin, I'm betting against economy. I'd rather have Bitcoin than dollars right now".
But Elon Musk is the guy that tried to cast his influence and succeeded even McAfee did not succeed on any coin that he wants to hype because he prefers to hype new coins where he gets paid for shilling it, Elon Musk did not get paid for promoting Doge but he made a lot because he is a huge bag holder of it.