This is not the first or last time this question has been asked on the forum. Everyone who learns about Bitcoin asks this question, but not everyone who has learned the answer to it has invested in BTC. To invest in bitcoin, you will need to study the DCA strategy, which, as time shows, is the best.
I think it is a question from people who are confused and lack understanding of what Bitcoin is all about. If one doesn't understand Bitcoin very well, especially the volatility of Bitcoin, and understands Bitcoin as being reliable and safe, trying to understand the DCA method of investing won't be of any use because a proper understanding is the first step to approaching Bitcoin, and the next step is to think of a strategy for how to invest in Bitcoin. Understanding Bitcoin and its volatility has been the challenge for beginners, but once it is better understood, how to invest is not even a problem.