Did you also tell them about risk and volatility, if you don't tell them they can get overexcited and take wrong steps if they make up their mind to invest. You explained Bitcoin to them in a good way, you told them it is a currency rather than a money making investment, the right step should be learning Bitcoin as a currency first, then other functions can come later. At your parents age it is unlikely that they would want to use Bitcoin, but one must not use it to have knowledge of it.