You don't. Just tell it like it is. Its potential is blindingly massive, but its decentralization means it could theoretically die in an instant. Don't tell them it's a guaranteed way to grow your money, because it isn't. Tell them they should only put in money they can afford to lose at least at first.

If they're not blind haters, then they should at least consider it. Otherwise, well, it would be a complete waste of time. You are not gaining anything either, so do not bother.