well i think they are, there is a rumor that Zuckerberg is investing in bitcoin. And hell yeah they know that it exist.
I know that too. Also Trump is investing in Bitcoin too

(joking ofcourse)
there are huge funds and most of billonaires dont know what are they investing in. They just look for interests.
And fund managers will drive money to BTC or any other crypto currencies.
Agreed! Billionaires are just concerned with interests. They need profits nothing else. So many billionaires must be investing in bitcoins in order to double or triple their money. These are the people who are called big whales of the crypto world. Its nothing awkward for billionaires to invest in bitcoins.