DCA works with investments that have decently good chances to have an ongoingly upward price curve, such as bitcoin, yet it does not necessarily work with any of the shitcoins because an overwhelming majority of the shitcoins tend to be trades rather than investments, so DCAing is not necessarily a good idea with things that are trades, rather than investments.
In the case of Shitcoin, the DCA method is never effective, because Shitcoin has destructiveness. But Bitcoin is Bitcoin, there is no alternative, the longer you hold it, the more suitable it will be. These things are certainly easy to understand for everyone, the way you explain it is very clear for beginners.
So the longer Bitcoin is, the more profitable it will be. And the DCA method is the most effective in Bitcoin, moreover, this DCA method is not effective anywhere else. If the DCA method is followed in crypt, then that investor will lose all the capital.