To me, cryptocurrency just looks like a scheme. At the end of the day, we collect other people's money and call it gain. IT IS WELL!
It sounds like you are not sure of what cryptocurrency is all about or there are things you want the forum members to explain to you.
Now, for learning purposes, a Scheme, as you mentioned has different meaning or interpretation, but with regard to Cryptocurrency, it could mean, a plan or a program of action, especially a Craft.
Notwithstanding, nobody collect money from other people, earning on the crypto community is absolutely individuals efforts.