Conscious application when investing in cryptocurrency is very important even though you are trying as much to buy the dip. A lot of cryptocurrency traders are just buying blinding even when they have little fund to invest in cryptocurrency.
Just imagine that you are earning $1,500 a month on average and when you remove your utility bills and miscellaneous bills, you are left with $200. Now if you want to invest in cryptocurrency, you are not expected to use all the whole fund to buy Bitcoin. At least you can divide the $200 into two and invest $100, while $100 is left as an emergency fund so you don't have to go sell your Bitcoin portfolio just because you had emergency bills to settle.
We ought to be very wise when investing so we don't keep making the same mistakes over and over again. There are people that would invest all their saving in cryptocurrency due to lack of knowledge about the crypto market and when problem comes, they would have no option than to go and withdraw fund from their investments which is very wrong.
Citing your example, if you allocate all $100 to emergency fund alone, it would not be a good practice since there are some needs which are not part of your immediate expenses and which you must plan for by creating a variance of backup fund for it like House rent which is paid yearly in my country, if the house rent is $300 dollars per annum, you'll have to allocate $25-$30 from the $100 left after investing into bitcoin specifically for the house rent backup fund and such goes to other variances in accurate percentages and hopefully by the time you're done you may end up with about $30 for your emergency fund or thereabout. Emergency fund is built over a period of time until it can take care of at least 3 months of your expenses, and you don't have to neglect some important variances of backup funds because you're building your emergency fund. Everything should go synchronously.
Who is wrong? Did I gave an explanation on how he utility was being spent? Why are you making uninteresting assumptions about how a monthly salary need to be spent? Even though you need to pay for your house rent utility bills, are you telling me that your monthly salary (if actually you have a job) could afford to pay your annual house rent bill when summed and take care of other bills?
Don't confuse yourself because I only made use of a scenario where if you are being paid monthly salary of $1500 and when you removed your utility bills and other bills, you will have a left over of $200. You don't have to use the $200 ans invest in Bitcoin. You can always divided it into two and use half for investing and keep the remaining as an emergency fund. That is after you have removed all necessary bills including savings.