You are absolutely right that it is important to have an emergency fund so that we do not have to sell Bitcoin at a difficult moment and of course we must have an emergency fund before investing. There are most new investors who enter the investment but do not make their financial plan and emergency fund before entering.
Yes having an emergency fund is important when investing in Bitcoin but it's not a must to have it first before getting started into accumulating Bitcoin, what is most important at first is having your discretionary income this is what you use in accumulating Bitcoin then on the process you can think of setting your emergency fund gradually by then you have already been accumulating Bitcoin with your discretionary income either using the DCA strategy and HODL.
Never does a person buy using HODL. HODL is to hold until your time limit after investing, so it is to continue buying continuously through the HODL.DCA method and hold it for a long time. But HODL never helps us buy.
We do not need much to invest. We have a source of discretionary income, basic knowledge about Bitcoin, and faith in Bitcoin. If we have these things, then we should never delay investing. An emergency fund can be created along with investing. An emergency fund is not something that needs to be in advance. And if a person already has an emergency fund, it is very good. But it will never be the right decision to create an emergency fund by stopping investing.