I would not necessarily say its a lack of knowledge but this things are caused by ignorance, where by they know this things already but they wouldn’t consider themselves having a sustainable bitcoin investment, what should be the reason for someone to diversify using his emergency funds to do that, but in a nutshell people who have a different thought of diversification withholding there reserved funds and also saving fiat might just be a different strategic and institutional situation of diversification, emergency funds should just be there to protect yourself from emergency liquidity. Using emergency funds for other different investments purposes are totally unnecessary and it would be a bad decision that would be very detrimental to your bitcoin portfolio.
This is not just a decision that will be detrimental to your Bitcoin holdings or investment it's too unwise and it's suicidal to be doing such because the emergency funds stands as the last layer of protection to your Bitcoin holdings, so using it to diversify into something else make that fellow not just unwise but also pathetic.
Just imagine that the moment you use the emergency funds for something else, a serious life threatening emergency situation arise that needs serious money, in that situation nothing can save his Bitcoin investment, he must temper with it, so this is one of the reasons why the emergency funds should not be used for anything else except real life emergency that threatens your bitcoin holdings.
A Bitcoin investor should only be thinking of diversification when he has gotten to his over accumulation status, that's when he or she can start thinking of diversifying into land or real estate etc. you don't diversify when you haven't even achieve anything in your Bitcoin investment.