Would you sell your coins daily or save them for some time?
That depends if you need money to use today, then sell some today.
That also depends if you feel that the price is good today, the sell some today.
That also depends if you are already rich, then you don't have to sell and save it for a long time to get even richer.
I personally would sell for another time but this is depends on the miners I suppose , they spend millions of dollars on those things and I'm pretty sure they have some daily expenses as well so It's pretty much not that easy.
some people also keep saying that miners may shutdown if the price goes low so It wouldn't make sense if we say they are holding them for long term.