people wants to earn a huge amount of profit and because of that, bitcoins should increase even more in the future in order for people to get ROI in their investments.
If people wants to earn huge in such a volatile market then they should know when to take profits. The problem is that some are hoping for a continuous increase in price and when its price dump, that's the time they would panic. One should take profit when the market is still green. Well that's the nature of people sometimes because we are an emotional being so when there are panic sellers, we tend to panic too and sell. Just like what OP said, one should take profit from time to time so that we are sure that we can have ROI even if we hold the asset for long term.
It's important because it creates an atmosphere of continued growth and progress. It's also a sign of more positive returns. Though, it's not that predictable, we must learn to control our emotion and not to panic. It's good that we have an idea to what's the proper time to buy, hold, sell, or invest, and on what's the proper way to manage risks and losses.