It can be more effective when you have a strong backup fund and sufficient cash flow. There is nothing wrong with buying in a falling market, but waiting for a falling market or planning around a falling market can prove you wrong and if you fail to catch it, you can take the wrong steps which can cause you a lot of losses. A market fall is a good opportunity for every investor to stock up. Let it happen naturally, when you try to buy the dip artificially, you can be forced to take the wrong steps. Because you do not know when the dip will happen and how long it will last. Here you are more likely to panic and there is a higher chance of hurting yourself.
The market can go down or up. If you have a solid plan that you've stuck to from the beginning, this shouldn't affect you. For example, if you said you would buy Bitcoin on the 3rd day of every month and you're buying it, don't postpone it to the 4th day just because Bitcoin has fallen and might fall further. You can't predict when the decline will stop and the rebound will begin. Instead of wasting time on that, stick to your plan. When you see how many coins you have in the long run, you'll naturally stay away from the temptation of daily trading. Everyone makes plans, but very few people stick to them.