Steady income => steady investment process => good chances that you are going to be okay if the trouble eventually hits.
Fixed income can be divided into two or three important parts so that you can run your investment in Bitcoin without being disturbed by emergency needs or by problems that can befall yourself. So in such a case, you only need to divide your own fixed income to be able to do three important parts without sacrificing one of them even though a problem comes to you.
It doesn't matter if you have a steady income or not, if you don't prepare for the days you will be in lack, or in serious health issues that might compel you to temper with your Bitcoin holdings, in a situation like that, if you don't have emergency funds in place to sort it out, your Bitcoin holdings will not survive on the longer run because emergency situation is inevitable on the longer run.
What you said is clearly true, because emergency funds are also part of self-rescue that can be useful in maintaining Bitcoin holdings that we already have so that the amount of our holdings will not immediately decrease just because there are problems that start to come to ourselves. So I also agree with the idea you said because the benefits are also quite clear for those of us who are confident in long-term investment in Bitcoin.