I believe people who are waiting to buy the dip are short term investors (more like traders) who are only after profit so they believe buying cheap and selling after a little price movement is the best way.
You can wait to buy at the dip if you have reached your bitcoin accumulation target and wants to go into over accumulation stage. Also, when you are in your over accumulation stage, you can buy bitcoin at the dip in order to replace any quantity that you sold for a good reason and buy back when the price dips so that you don't go below your over accumulation stage and start accumulating bitcoin again with DCA regularly.
Over Accumulation? Are you for real? There is no such thing as over Accumulating, when your target is reached that is not the end of your investment journey you just have to reassess your goals and set a higher target. That way there won't be an over accumulation. If your target is reached you can decide to take some profit and rebalance your portfolio if you see the need to but i think extending your investment period is wiser since Bitcoin has the potential to grow even higher. Taking profit doesn't mean you sell all your Bitcoins.
Reaching your target doesn't mean you change your accumulation strategy and start buying at dips. Reaching your target doesn't mean you should relent on your accumulation.
Funny enough you said there is no such thing as over accumulation but in my reading of your post it seems you have made narration of it in a kind of way, when we feel that we have spent a reasonable amount of time and resources in to Bitcoin we can strike a balance and conclude that we have gotten or transited to being over accumulated stage based on our personal circumstances, we can as well only be maintaining our portfolio too and maybe can only be buying the dip which of course there is nothing wrong with that.