Sometimes non-urgent matters can send you a warning that you better be careful about how much you put into bitcoin, because sometimes things happen... and for example, you might have been using a computer and phone as your main communication devices, and they are used for work and for pleasure.  You might even have a back up computer that can serve some purposes, but your back up computer is inadequate for your main purposes, and if your computer breaks down or gets stolen, then maybe you have back up files, but you still need your computer in order to do the work, so all of a sudden you have an expense that was a bit outside of your expectations, but if you don't replace the computer, you are going to be less efficient in your work and you might even lose income based on your lower efficiency.  So you may well end up having to dip into both your back up funds and your emergency funds, and you find that the replacement of the computer taught you a lesson about how much back up funds that you needed to have available, and surely you will be lucky if you are able to replace your emergency funds and back up funds within a few months and before another emergency happens, since you might imagine that when you deploy money from your emergency funds and back up funds, that money is no longer available and has to be replaced to merely get you back to the point that you were prior to your computer breaking down.  You also might realize that you have aspects of your data back up system that are inadequate, so maybe you have to buy another back up disk or some other extra expense that came to your attention ONLY after you had gone through the broken computer situation.

Like you mentioned, some expenses might be deferrable like maybe you need to get the computer right away, within a few days, but the back up disk (system) can wait for several weeks, even though you consider it as a needed upgrade, you have a currently working system in place, even though you came to realize that your current system is not adequate.