Bill Gates of course, he moves millions, but don't understimate the power of Mike Tyson. He is not only one of the best ever in the sport of boxing, he is part of American culture and a legend, thanks to this now millions of people will be aware that at least Bitcoin exists, so this is indeed awesome news, a great publicity stunt for Bitcoin.
And never underestimate Tyson's influence to teenagers.That dude was wrestling, had cameos in several movies.Even my niece knows who Tyson is.She just got 12. But she has no clue who Bill gates is although she knows a lot about tech for her age.
So both are important I would say. Both guys bring different types of people into our ecosystem.And only that counts in the end.