Not a good idea going short on bitcoin futures if price suddenly increases. No one knows when price decrease or increase. So, it is hard to go short on bitcoin futures. It is safe not to go short unless you want to loose your hard earned money or bitcoins.
no one knows but we can predict the changing of the price so that helps out a lot when deciding to sell or hold
if anybody
could predict that, that person already would have been the richest man on Earth. What you mean is speculate, not predict, and there is a long way from speculating on something to predicting something.