I agree with you 90% of the time. Everyone needs to have an emergency fund if you are not already a wealthy person. That is, if you are one of the richest people in the world, you may not need an emergency fund. But if you are an ordinary person, then adding an emergency fund to your financial management is the most necessary. You may be having a positive moment in life recently, but will such positive moments last forever? In this case, I would definitely answer no. Because this is not a characteristic of a human life. The characteristic of life is that you will have both ups and downs in your life (potential).
I do not see any alternative to having an emergency fund in your financial management as a plan for such potential moments in life unless you are a billionaire or one of the richest people.
The comments you have mentioned are not reasonable because those who are not only rich people need Emergency funds who told you. Emergency funds are essential for everyone, even if he is a rich person. Emergency funds are not only necessary for investment, but also in our lives, many times suddenly need a lot of money.
One thing to keep in mind is that at any time in everyone's life, money is suddenly needed, that means hard times are coming, therefore an emergency fund is being created so that everyone can get through that time properly. It is also in the case of investment because when purchasing Bitcoin, when the amount of cash flow is temporary reduced in our hands, we are able to continue the investment using that fund.