You should not send all your money to buy Bitcoin, you need to start with a comfortable amount so that it does not create any inconvenience for you. And even if you wanted to increase the amount you set aside for a purchase, this should not be the last one you have, you should think about the fact that for some reason your investments may become inaccessible to you. What will you do in this case?
Make sure that you always have savings that you can use if necessary, I prefer it to be cash that you will always have access to. Even if you always have access to your investments, this money will be useful to you if some kind of collapse occurs in the market, you will be able to buy more if you want.
Invest only that you can afford easily. Don't made yourself uneasy with your investment capital and go for things like borrowing money. Investment must be for larger duration and you can afford that only if you make things easy for your self. You can reduce or increase investing money based on your income.
I do agree that we must have two type of savings one is for bitcoin that is for long term and second one is for daily life necessities. For second one you can spare cash or invest in things like buying a health insurance for the family and more. Saving money won't be of any use but investing them for a long duration will definitely increase them.