Even if he believes in it, I think making this kind of wager is extreme. There are multiple other ways to emphasize your confidence.
$1 Million does look extreme. He has revised his prediction of $500K by 2020 to $1 million by 2020. And he has done this based on Bitcoin's strong rally in 2017.
He has really been an ardent believer of bitcoin right from the onset and his predictions have been out of this world. However, I guess we will just have to wait and see if he ends up right or wrong. 2020 is just by the corner, but even if he is looking at the trends and the way things are, that sounds pretty insane, but not like if it happens, no one will be happy.