If a person has lump sum available, such as $1k to get started, and maybe he has an income in which he can buy $100 per week in bitcoin, then with the extra $1k, he does not need to invest through DCA, he could buy right away and/or he could buy at the dip (if the dip happens), so he has choices of the three different styles, and DCA is not always better if you already have a lump sum of cash come available to you. One of the reasons that so many people use DCA is because it is much easier to tailor some kind of a buying amount that goes along with their regular income coming in and their expenses, and so DCA also will allow an adjustment every week or whatever period that a person chooses to buy bitcoin under that kind of an approach/practice.
Yes, if a person has $1,000, he does not need to follow the DCA method, he can buy from the depths of the market if he wants. DCA will be a good method for those who will invest using the equivalent of $100 every week, but it will not be very effective for those who will buy from the depths. If I have a large amount of money at one time, then I will definitely reflect that when the market falls, and it goes down a lot, I will invest with all my money. If I can buy deep, it can show profits in a very short time, but if I use DCA every week with my money, it will not give much profit. So if you have cash, it is better not to practice the DCA method in investing, but it is better to buy when there is instability in the market.
The way you are stating this is very wrong, the fact that someone has $1000 doesn't mean they can not use the DCA method again off course they can and as a matter of fact if that is your income for the week or month all one need to do is to get a discretionary from there and invest instead of going all in. But if your income is more than this by X then using $1000 from your discretionary to go all in won't be bad as long as it is coming from your discretionary. If you use all your money that is money outside your discretionary to buy Bitcoin when there is dip, you will surely see the ugly side of your action and trust me it won't be nice.