Ya setting aside emergency fund should always be part of the plan when trying to invest invest into Bitcoin but you can still start up your bitcoin investment if emergency fund is not available as long as your discretionary income is available then gradually you can start setting up your emergency fund when you have already started accumulating Bitcoin through your discretionary income.
The reason to plan for emergency fund is that certainly in life we will definitely come across unexpected issues that we will definitely want to solve without selling out our bitcoin holding in a short while so it can easily be sort out with your emergency fund.
Their is an adage in my country which say;
he who fall to plan, plan to fail.When it comes to Bitcoin investment, having an emergency funds is a must, because without it, it's very likely that in the nearest future you will fall back to your investment anytime their is an emergency, so it's very necessary to have an emergency fund aside from your decretionary income, so as to be able to wether the storm if any emergencies arise.