It is true that bitcoin is not just a life changing coin but also a life saver. Just like you, I save my bitcoin and use it for special purposes only by converting it into cash. There were time that I have to pay for my sister's school bill and glad that I have some saving in my wallet. It is very advisable to save for you child and even for yourself it maybe fiat of bitcoin. But I prefer bitcoin.
There is not much of a point in saving in fiat, all your fiat must be invested in something, real estate, stocks but the market that is giving the biggest earnings is definitely bitcoin, so save all the bitcoin you earn no matter the source and convert most of the fiat that you can afford in bitcoin, that way in the future its value would have multiplied and you will be able to enjoy the fruits of your great investment.