I think that they do not miss the opportunity to get even more profit by using crypto currency. Perhaps someone even became a billionaire thanks to investments in bitcoin.
There's no doubt that billionaires also invest in bitcoin. They will always find ways to triple their wealth and investing in a cryptocurrency is one of their way also of multiplying their wealth aside from investing in a stock market. They will still monitor its price in the coinmarket coz even though they're billionaires, they still don't want to reduce their wealth.