I'd want to write a book for the general public, and people love stories more than anything else.
Biography of a Bitcoin millionaire. How he discovered it, what made him believe, how he felt, his poor childhood growing up. Class-hopping. It'd have to be spiced up and a bit dramatized.
Bitcoin Hacker. Bitcoin is a hacker's dream, irreversible bits on weak connected systems. I think I'd forget the straight facts here and just write some fiction based on true events. Write about the geeky childhood, the dark nights, the discovery, the rush... the struggle, the late nights pumping techno. The final victory. The fear. The mix of guilt and excitement. The secret and pride of wealth... that could never be openly shared.
Bonus points if you can take these two and juxapose them. The honest Millionaire who looses everything verses the looser who smarts himself a fortune.
Take a story like that and give it to someone 10 years back and it'd be straight science fiction. But these are the realities of what's actually happening today.
Bitcoin = unlimited demand and limited supply (maximum 21 million)