When it comes to bitcoin investment there are things that are important to have and one of them are reserved funds, like you said it helps one when there's a dip, when you are using the DCA strategy and you have also built a very good reserved funds it will help you accumulate more Bitcoin than someone who is just using the DCA strategy without any built reserve funds.
Reserve fun is very important but not to be use the way you are saying because every investment strategy has there advantage and also disadvantages and any wrong decision can result negatively on your investment, so your reserve funds shouldn't be a strategy for investing all in any Bitcoin dip because doing that can result to the disadvantage I'm emphasizing on, so actually I don't really see any risk on Bitcoin holding but most of the people are the ones that's bringing the risk to themselves because if you're accumulating with the normal method without adding any greed I don't think there would be any regret but the ideas to navigate into other method in other to stack more Bitcoin has always brought setback to most people.
Actually the only way you can know that Bitcoin has dipped is when the price reduced below the amount you have it bought earlier, so this means if someone has invested on Bitcoin when the price was $60k and the person has reserve funds already. Probably when Bitcoin dips, the person can choose to use all his reserve funds to buy Bitcoin at once because as it is now, Bitcoin can not go below $50k so if the person didn't buy Bitcoin with all the reserve funds when bitcoin dipped to $55k because he is thinking that Bitcoin will reduce to $50k before he buys with all the reserve money that he have, it means that the person is skeptical about the kind of investment that he is doing.
If you choose to invest on Bitcoin you need a good strategy and a good plans so that you can succeed on the investment, an investor can decide to invest on Bitcoin through DCA method and also keep some reserve funds so that when Bitcoin dips to the kind of amount he wanted he can use the reserve money and buy enough Bitcoin.
Actually, for those that are investing on Bitcoin with lump sum strategy, I think it would also be better if they still buy with DCA method, because most times Bitcoin keeps skyrocketing and if you are waiting for a dip before you invest you might miss a lot of opportunities, so it will also be nice if you DCA to buy bitcoin gradually and anytime you experience the dip you can then buy will all the money you reserved.