Sometimes it is easier to read a physical copy of a book rather than a digital copy.
Additionally by purchasing the physical copy you are supporting the author for their efforts of gathering all this information in one place and explaining it in simple terms.
I also have the physical copy of Mastering Bitcoin with me but in my case I downloaded the PDF file and print it out from my printer and yes it's easy to read from physical copies that's why I have also done the same when I was reading it.
I don't like the first reason but I would agree to the second one. We want to have our own bank with Bitcoin but in society, newbies are vulnerable to scam projects. To protect them, primary solutions as regulations from governments are good.
Many small nations are likely to pass the crypto regulation bill in their parliament and some have already adopted it like El Salvador and what I was talking about was some years later when majority of government would come up with these regulations instead of putting a ban on Bitcoin.They will continue with all their centralized system of CDBC but yes BTC would be mainstream everywhere in the positive scenario.