If you trade without stop loss or target you would get in this situations where you panic and don't know what to do.
When you have the stop loss and it is in good position lets say 2% of the balance you would not lose but with strategy you could predict where maybe the price will drop or get higher then. The same with the target you need to know where to take profit. Not just waiting and waiting. If you buy to hold on to a Coin is other thing.