For the same reason some people line to use linux when windows works everywhere. Actual technical use cases, ideology, and 'tinker-friendliness'
1) there are some use cases where it is better (typically when you want to do something that the state doesn't want you to do)
2) there are ideological reasons to prefer decentralized ownership of the financial system rather than assuming the state can be responsible with the dials and levers of that system
3) There are neat properties of crypto that are fun for tinkerers - money is programmable and you can do neat tinker-toy things with it like micropayments, fintech like collateralize loans and decentralized derivatives trading, dumb things and experiments like the old peepeth, etc.
I think eventually if adoption is wide enough there will be society-altering implications inherent to crypto but for now I think it's those 3 things.