I wouldn't read too much into it. His comments about cryptocurrencies in the past show that he has no stake in crypto and didn't spend much time getting acquainted with the technology. My guess is that he either received the book as a present or is simply catching up with recent developments.
I know his comments always stated that he has no position in crypto. .But maybe he meant that he is not trading or holding anything but I think he has an interest in blockchain technology. I mean i am pretty sure that the Tesla cars could use it for tracking the vehicles and their usage and who knows what other usages there might be. I just thought that it might be an interesting discution.
Elon Musk taught himself computer programming at the age of 12, so he is familiar to the concept of self study. 
You have to remember one thing, he founded X.com, an online payment company and they later merged with
Confinity in 2000 and became PayPal. So he has very intricate knowledge about online payment systems. I should think that
he would be interested in new ground-breaking technologies in the online payment scene.
You have to remember one thing, he founded X.com, an online payment company and they later merged with
Confinity in 2000 and became PayPal. So he has very intricate knowledge about online payment systems. I should think that
he would be interested in new ground-breaking technologies in the online payment scene.
Yes. That is an additional factor that makes me believe that he just wants us to believe that he is not interested.