In fact, if you hold on long-term, the risk will be very low, but not risk-free, of course there are some risks involved. Now the DCA strategy is the best strategy to invest in Bitcoin, if someone plans to invest in Bitcoin then if he chooses DCA strategy then there is no need to wait for his price to fall, because investing in Bitcoin in DCA method will be able to buy at average price. If you invest in DCA method, you can gradually increase the amount of investment, if someone continues to invest in DCA strategy with a small amount of money, then at some point the amount of investment will be quite large. Now the investment has to continue with DCA strategy and long term plan. I've heard the stories of some people who invested in the DCA strategy on a weekly basis but weren't able to hold on long-term, because they didn't have a long-term plan, so whatever method you invest in must have the ability to hold on long-term.
The DCA accumulating strategy is wired to be a success on the longer run, so anyone that really wants to be successful in his investment while investing through the dca accumulating strategy needs to have it at the back of his minds that he must be thinking long term.
Concerning the bold statement that you made, sometimes it's not about having a long term plan or not, it is about putting down measures to safeguard your Bitcoin investment against any unforseen circumstances that may warrant you to temper with your Bitcoin investment, that is why sir jayjuangee has always emphasize on the importance of emergency and reserve funds in Bitcoin investment, because emergency situation will definitely come, but if you don't have it in place to protect your investment, your Bitcoin investment is doomed if any emergencies arise while investing.