Trading and DCA has nothing in common DCA is a process used in accumulating bitcoin and most of the people who use DCA process are those who want to buy and hold for long time so I don’t see anything wrong with saying DCA has something to do with bitcoin holding. But for bitcoin trading you don’t need to follow DCA at all you just need to use the money you have at hand enter the market and start their trading losing or winning, so i don’t see any relation between DCAing and trading that’s a wrong connection if you ask me.
I also think like that because logically, people who are trying to collect Bitcoin and hold it for a long time don't immediately think about selling in the near future, so it is very feasible to use the DCA method in that case. Meanwhile, trading is a very different job from collecting because the people who trade in the market are people who are targeting profits in a short time or quick profits in a certain amount so it cannot be compared to people who are collecting Bitcoin by run the DCA method.
Though you have made some point here, but there is something I notice some people have different wallet and some of this wallets are used for accumulating more bitcoin no matter how small and no mindset of selling soon which real definition is long-term holding and the other wallet, they use Bitcoin that are their to trade for possible profit which we may not know about, I thought about this, I noticed that many traders are core bitcoin hodlers because most of them knows the benefit attached to hodling for a long term, though hodling and trading works in a different direction.