Some investors are generally interested in buying more BTC at DIP prices and tend to sell during bullish times. But holding is more important because it will happen again and again when ATH is observed in the market with gap of few months. A bullish period is characterized by overall market optimism and expectations of higher performance for the future. Even offers higher returns than bearish ones. A bull market usually reflects the utmost confidence of investors that a person can align their investments in this positive trend. Increasing market value makes investors optimistic about the positive loop. These positive market conditions may prevent investors from being psychologically tempted to sell BTC. It can even discourage selling during market downturns. Many investment firms can build potential wealth by investing more during periods of BTC price appreciation.
We cant deny it, most of the investors is tempted to sell during dip when they saw thier portfolios losses 50% of its value it is because we have fear, instead of buying more coins they are tempted to sell because they think that dropping of price continue and they don't want thier funds to be loss forever, this is the reason why most of the investors loss and only few percent of them earn.
They will suffer the most when they sell their investment for fear of further losses because if they had been able to hold it patiently for a long time it might have recovered and even made a profit. That is why we should acquire proper knowledge about investments before investing. And we should control our emotions while investing. As you mentioned, if an investor's portfolio falls by 50 percent, it is a matter of concern. In this situation, bad thoughts will arise in everyone's mind and even they will be tempted to sell it. But if they can patiently hold the investment like a seasoned investor during this tough period then they will see success when the price of Bitcoin increases.