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.
I get your point, but if one actually have some nice amount of money he or she can use to go all in like a form of lump-summing to give their accumulation some nice boost , they can actually go for it without them overdoing it like using their emergency funds. Reserve funds is not all about going all in though , one can choose to spread his reserves funds when. Purchasing, incase there's a further dip .
For instance I have $50 as a reserve funds I can choose to break into $10 , So bitcoin price was around $65k then dip to $62k , i can just purchase $10 worth of bitcoin , leaving me with $40 then I Will purchase again if any dip occurs with $10 from the remaining funds till the $50 eventually runs out.