The back up funds help to make it possible to not tap into the bitcoin and for the investor to meet his goals... so they likely are building the back up funds as they go in the event that they do not have back up funds prior to getting started with bitcoin.
Very helpful and very important. In my opinion, a reserve fund is one of the things that must be considered, prepared, and never forgotten if someone wants to get involved in Bitcoin accumulation. You've already stated the goal: if something unexpected happens in life that requires you to spend money, your Bitcoin accumulation will remain safe because of the reserve fund; you won't need to sell it.
This strategy or preparation is very helpful for investors in achieving their goal of maximizing long-term profits.
You are right about this because reserve funds are important but there is a little thing I want to add. A Bitcoin investor who do not have the financial muscle for that can still make do with just emergency funds. This is because if we stress the reserve funds too much, those in that income level might think that without reserve funds they cannot start their Bitcoin investment. Hence reserve funds should be setup when it is possible and it should not deter anyone from starting his Bitcoin journey. Emergency funds, as I have found out is completely indispensable for any long term investor, so it should be out in place as quickly as possible to protect the investment.