Yes absolutely billionaires invest in btc. It is a yes but not for all, some have enough to do with their fortunes. Some are very interested investing in this project because the price is high and it will make their capital more bigger in terms of value making it double, tripple or more. They can buy more cheaper price and selling it at a good price. They create projects to help their workers at the same time doing a good business helping others and earning from it. That's the business motto where their money will grow more then they will put more. To think that investing in this project is just one of their businesses, they put their money to where it will profit more.