Investing into Bitcoin with funds that are meant for your expenses or other necessities is a bad investment practice. It can further be described as being over aggressive in your investment and it can prove unsustainable for long, also it can lure the investor to tampering with his portfolio when the actual needs arise and sell at a time he didn't choose.

Bitcoin is best approached with discretionary income, in accurate cashflow management practice, you must first remove funds that are meant for your expenses before identifying that you've discretionary income and further splitting your discretionary income into funds for Bitcoin buying and others for building of backup funds.