If you do not to rely on the mined coins to make a living, it is better to just hold the coins for the long term.
Yes, I agree with you that if it is not the only income that you have it is much better to just save it and wait for the right time to sell it when its price is high.
Or you could sell some of it if you have many and try to grow it by investing it to some good investment sites. It would be nice if while earning it you could still earn some from it by trying those bitcoins to work for you.
Saving them for future is a good thing, but you also need to take benefits from price fluctuations, sell when its allowing to make some profits and buy again when price drops.