Indeed because investing in anything using emergency funds will not recommended. The mean of emergency funds is covering our urgent needs that need money so we can use that funds and fill it immediately. The emergency funds specifically for an urgent needs and not for other things. So we have emergency funds and a free money for the investment with other money that we prepare to fills each needs we have. If we can allocate the income to the right place and know how much money we can allocate, we can use the income proportionally.
It seems you misunderstood a point that people mostly invest without reserved money as their emergency fund. It's different than they have an emergency fund that was used for investment and I hope you see difference here.
At least people had emergency funds but later used it for investment is better than people who never minded about having an emergency fund. They practiced badly by lacking discipline to maintain their emergency funds but if they can improve their discipline, they can do it better in future.
For a first type of investors who have never minded of having an emergency fund, they must change their mindset and break this barrier first. Then they might have their first ever emergency fund and move on with same mistakes like a second type of investors aforementioned.
It's wrong for you to use your emergency funds to accumulate bitcoin, neither should you have your bitcoin investment without setting up an emergency funds after you have started investing.