Holding bitcoin is not always good, especially for a long time because we never know what will happen to bitcoin and the price too. On the other hand, if you holding it not for a long time and you keep checking the price, you can make a money on it. I'm not saying holding bitcoin a long time is not good but if you look at the price right now, do you think the bitcoin will increase again soon ?
If the past performance is any guidance, the price of bitcoin will rise in the long term.
Past performance can never be of guidance, the bitcoin market is way too chaotic and volatile. You can also argue that bitcoin can become obsolete, as its price increase has been derived mostly from the hype for a new technology. This hype can wear off unless bitcoin progresses technologically.