Do we need to understand how something works before we can use it?
My opinion (which is pretty unpopular) is that it is not necessary. People are using money every day but they don't need to be a financial experts for it (tbh about 99% of them don't even know how work the economy of their own country), people consume different products without a solid knowledge what they are made of and how it will influence their health etc.
How can i explain to my 60 years old father to invest part of his pension in cryptocurrencies.
Imho it sounds like a very bad idea. If people are already investing their pensions into cryptocurrencies then the cryptomarket is definetely in a bubble.