Investing in bitcoin needs to be tailored to each person needs. While DCA strategy can work well for some. Each person has their own financial goals and comfort level with risk and investment timeline. It is also important to remember that people can change their investment approach as they learn and become more confident. Your example of someone starting with DCA and then switching to lump sum investment after learning more is great example of this. At the end most important thing is to find investment strategy that works for each person and allows them to buy bitcoin at their own pace without putting their finances in danger.
Because in Bitcoin investment, methods such as DCA or lump sump, it is just a person's approach to how to invest in Bitcoin and how they can adjust it according to their financial condition and their confidence. In the long run they can change their approach to investing in Bitcoin, they can choose DCA or lump sump, whichever is free, the most important thing is how they set their finances so that they can invest regularly and not sell just for short-term profit.