Hmm, an interesting idea but the only side effect I see about this your thought would be the fact that not everyone knows your how to manage their resources quite well and by the way, money has a way of getting involved into other unnecessary things you don't plan for especially when you are just hoping to use it for an upcoming action. But notwithstanding the idea is not bad at all because the ratio of you losing and also maybe having regret will be at minimal that's if you actually stick to your actual plan of buying with half the funds and waiting to see how the market turns out (dip) to buy more.
I see it as a complete good idea, better than just waiting for the price to dip before you can buy, which could lead one to lose entirely, but this method will help you to at least have something that you can hold onto for the main time.
Money has a way of being spent unexpectedly, like I said above, "Amount set aside for the Bitcoin buying." This money is separate from what one might have on his reserve for needs and wants that might arise, since man's wants are insatiable. If plans are being made properly, there is little to be worried about.
But if am to choose I think I will just go with the DCA strategy knowing fully well am heading somewhere and only the thought of adding to my investment by every little fraction will be on my head and that way if the price pumps I gain and if it still dips I continue buying and so doing increasing the amount on my portfolio slowly for the actual mega pump that will profit me.
The DCA strategy still remains the best option when we want to talk about Bitcoin accumulation, but I don't see it working on this pattern of buying where the person needs to wait for a dip in order to accumulate his or her desired amount of Bitcoin.