If every investors apply this, I think people would no longer complain about high volatility and asking whether they should sell or not.
Many people are too obsessed when they have money which they don't use and they're also greedy, hence they're trying to maximize the profit they can make by investing as much as possible.
It might be possible for some people who can still able to perform under high pressure, but most people seems not able to do that.
Exactly. If every investor understands this process, the case of losses that occur daily as a result of panic sales and premature sales due to emergency situation would become a thing of the past. People get carried away when they feel the market has dipped to their desired price and they go ahead speaking for every possible source of funds to invest while aiming at making a maximum profit. Anyone who invest with emergency funds is not ready for long-term holding, he's just a Trader parading as a long-term investor.
Maintaining your DCA approach is subject to your Discretionary income availability while the safety of your accumulated bitcoin stash is subject to your Emergency funds availability.