In most cases it's both. Like the people who were early to the Internet, they believe in a better world and they hope their early participation will be rewarded.
I was early to the internet, and the only financial benefit I ever expected from it was that I'd be able to have a good career because of the skills I'd developed.
I think early adopters more excited about being able to communicate in a fundamentally new way. The internet is more like the invention of the radio or tv.
Crypto is more like the invention of electronic cryptographically secure beanie babies with a semi-fixed supply.