That simple "line" holds historical significance in Bitcoin, although "some people" may disagree.
what if the price of Bitcoin keep soaring, are we going to still be waiting for the price to drop before we invest? What if in the process we spend the fund while waiting for the dip time to come? I think this are discouragement mindset and I see them as procrastination that tends to divert our attention from from doing what we ought to do whenever we are ready.
I believe you're applying the wrong attitude towards choosing a DCA strategy. A DCA investor accepts the condition that he/she can't predict the market, and therefore purchases an asset in a fixed amount/in regular intervals. Telling yourself, "what if the price of Bitcoin keep soaring", will merely lead you to FOMO.
If you are holding back money and not investing, then you may well be led to FOMO more easily than someone who is already investing (through DCA) on a regular consistent and persistent basis.