No one can tell exactly about big or rich people that use bitcoin but its quite understanding that bitcoin majority of prominent people in society actually using it, as business man or woman that know what is obtainable concerning business, I think its advisable to adopt cryptocurrency especially bitcoin and adventure into its investment or transactions for multiplication or avoiding of disvalue of currency in business, it obvious that billionaires don't feel reluctant in terms of investment, shall no one can tell how many of them are into  crypto network but is nice to invest in crypto.