Best way of explaining is using the gold analogy.
But I think explaining it to a person in his/her early teens will be quite diffiicult. Best to wait till the person reaches late teens and then explain
i agree i don't think it is not ideal to explain things like bitcoin to children, they should enjoy life at that moment without thinking about earning money their focus must be in their studies first. it is possible to educate them but teach them what is more important and ask them to choose their priorities in life.