If you pour all your money into investing and are afraid of the ups and downs of Bitcoin, you will be in trouble.
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.
You're very correct about the way you emphasized on splitting your Discretionary income into investment funds (for buying bitcoin) and back up funds ( including emergency funds). This is where many people get confused about bitcoin investment using discretionary income. So many beginners fail to understand that you don't even have to invest your entire discretionary income into bitcoin because you still have to squeeze out your backup funds and emergency funds from there before you can now choose your investment funds. You are not supposed to overly invest in bitcoin by using up all your entire discretionary income.
Investing into bitcoin with your supposed emergency funds is a bad decision that people make especially during dips. This is not supposed to be so if you want your bitcoin to be safe. Another disadvantage of investing with your emergency funds is that you stand high risk of selling your bitcoin at loss in the case of emergency situation of which no one would rightly choose to sell at loss if he has alternative funds like the emergency funds.
Cashflow management is a critical first step that every investor is supposed to be keen about. If you don't manage your finances well, it's either your bitcoin suffers serious loss or your responsibilities suffers abandonment which in most cases results in health situation that would still force you into loosing your bitcoin. An investor is supposed to be very conscious of the safety of his bitcoin stash by taking care of his responsibilities and making provision for emergency situations. Aggressiveness should not be done with any money aside discretionary income at all time so than you can possibly HODL for a long-term with initial holding target of at least 4 to 10 years time.