I disagree with you, even though DCA method is a very nice method of accumulating Bitcoin that doesn't mean there's no disadvantage and you should know there's nothing on planet earth that doesn't have disadvantage. I believe the reason why you said there is no disadvantage in DCA method is because of how convenient and reliable it is, and it has almost cover both the bad and negative aspect of it but I think one of the disadvantage of DCA method is that, if it is not done regularly it will really affect the time at which one would have gotten to overaccumulation stage.
One major thing i took note of about your statement is that everything in life has it's benefits and disadvantages, although the DCA is the best strategy for managing risks in Bitcoin investment but it still has it's own down side which is that someone that's not commited to tasks would find it difficult to invest with it since it's something that should be done consistently according to the period the investor can regenerate their discretionary be it weekly or monthly but in general the DCA is more positive than negative when it comes to Bitcoin investment, one thing i love about the DCA is that it helps an investor to invest consistently regardless of market volatility.