Not everyone is a cool person, nor does everyone have unlimited funds. Only when the market tide recedes can we see who is swimming naked; only in extreme downtrends can we truly test a person's investment level.
Moreover, during a significant market decline, one can only watch helplessly as the price of coins drops, yet cannot average down due to a lack of funds. This often stems from improper financial planning, which leads to a lack of coping ability at critical moments and missing the opportunity to adjust the layout.