It's as much real world usage, as people owning stocks and precious metals is.

> I can fully accept that 5-25% of a countries population is gullible enough to buy cryptocurrency.

In many countries, it's the 75% of the population saving in their local fiat currency that are the gullible ones. I know we all love United States Dollars, but in many local economies, there aren't enough of them to go around. Acquiring, storing and transacting with cryptocurrencies can be easier, and more secure and discrete than going to your local black market USD dealer and stashing stacks of bills under your mattress.