Well said, I believe there is no necessity why one will want to build an emergency funds firstly when he can invest with any little capital, and also build emergency funds along aside his Bitcoin investment. As you earlier said, we have no control over natural occurrences, same way we can't comprehend how far our emergency funds will go while investing or any unforeseen events happen.
There one thing we should understand, Emergency funds aren't fixed funds, rather are suppose to be liquid ( by that I mean continually growing it), not a fixed amount you think, in essence it is pointless and a waste of time to not invest when you can, you simply control your risk, leverage on your sources of income and build your reserves overtime.
I see the point you are trying to make and i am convinced, if a person can invest and build emergency fund all together then it is the best thing to do but then majority of people are struggling to make ends meet and are barely able to invest so building both emergency funds and investing at the same can be difficult for some. Building emergency fund will only delay ones investment reducing the possibility of buying at a lower price and that’s why DCA strategy have been of great benefit making it possible to invest at intervals and also creating the possibility to build emergency funds as well. It’s just about knowing how to balance the two and not be aggressive too aggressive with either leaving aside the other.