Investors create emergency funds so that they can maintain continuity in their investments. People can experience economic downturns at times and when a person experiences an economic downturn, they will naturally not be able to invest in Bitcoin continuously. But those who are very serious about their investments never want their investments to be irregular no matter how much economic hardship comes in their lives. That is why when they have a lot of money, they keep a part of that money aside and consider that part as an emergency fund. However, it may not be possible for everyone to create an emergency fund because not everyone's financial situation is the same or everyone's income is the same. Those who create an emergency fund and invest will undoubtedly be much ahead in reaching their goals, but those who cannot do so try to reach their goals.
It doesn't take a lot of money to build an emergency fund. If you want, you can build an emergency fund over a long period of time along with investing. For example, you can invest 80% of your discretionary income and create an emergency fund of 20%. You can build an emergency fund gradually and you need to keep 3 times your stable income in the emergency fund.
I think there is no greater fool than a person who does not build an emergency fund after investing. Because by doing so, he is putting his holdings at risk. Because if he does not have enough money to face a financial disaster, he will be forced to sell his holdings.