I think they know the existence of bitcoin, and surely they invest in bitcoin, because bitcoin is currently popular with its skyrocketing price, arguably it's an opportunity for billionaires to make a profit. But maybe not all billionaires are investing in bitcoins.
Of course, Bitcoin is truly a phenomenon and it is so popular in the investing world, it brings super profits, any investor can not resist its appeal, the billionaire is just the traders and investors, bitcoin also has great appeal to them, they will not miss a chance to make great money like bitcoin. So they invested in bitcoin is a sure thing, not long ago, I also think they only know bitcoin and they do not invest because they have their job, they have too much money, they do not need to invest in bitcoin, however, now I realize they are lying, they invest a lot of money in bitcoin, they even pump the price of bitcoin up dramatically to make a profit