The only way emergency funds should be used in terms of investment is if they happen to be excessive, and surely some folks might be labeling all of their extra funds as emergency funds, and part of their emergency funds might be reserves and/or float but they are labeling such as emergency funds.

So yeah there can be questions regarding how much emergency funds a person needs to build up.. and if someone is brand new to investing and brand new to consciously paying attention to building and maintaining an emergency fund, then the emergency fund might start out relatively small.. maybe just by coincidence normal people might keep a kind of float of 2-4 weeks of their expenses worth of extra cash that is kind of considered to be used for any any extra expenses that might come about.. but then once they start to invest into something like bitcoin, they realize that they are likely going to need to keep larger amounts, such as 3-6 months worth of emergency fund, but they are not necessarily going to get their emergency fund up to that size immediately, so they end up building up their bitcoin investment and their emergency fund at the same time.. and surely once they get their emergency fund up to a certain size (such as a minimum of 3 months), then they might begin to feel that they have more abilities to be aggressive in their BTC accumulations (adding to their BTC holdings) or even to use some of the excess (greater than 3 months amounts) for the purposes of investing into bitcoin or other kinds of purposes.. but yeah, if they are barely floating on keeping ONLY 3 months as emergency funds that are not touched for any reason except actual emergencies, they may well find that they are not keeping enough emergency funds since sometimes various expenses can come at the same time and quickly eat into such relatively lower level amounts of financial cushion... .so yeah in the end, there becomes more and more need to keep some funds in cash that never get touched because otherwise the depletion of such extra cash ends up putting the person closer and closer to having to dip into his bitcoin investment that might be at a time that is not at his own choosing.

I think that it is very weird to be failing refusing to consider reserves in terms of fiat, unless there are some folks who truly are able to spend all of their expenses in bitcoin.. or if maybe they have so much bitcoin that they are willing to just take the chances of keeping all of their value in bitcoin (presuming they earn in bitcoin), and so these seem to be less common kinds of circumstances, and there is a certain level of healthiness to considering holding and/or converting value into fiat.. since even if some expenses might be payable in bitcoin, they are likely calculated in terms of fiat.. so it does not even seem very realistic that we are considering some of the exceptional cases in which some few folks might completely earn in bitcoin and are able to spend in bitcoin and they just let bitcoin's volatility go where it goes, especially if they are already getting all of their income in bitcoin..