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
Yes ,it is so hard to explain to them especially if they are not interested to waste just like 2-4hours a day spending time to bitcoin .
But its easy to explain if the teenagers are openminded with business and money and they know how value each money that goes on their hands