It should be noted that I am not saying that buying strategies are not important. However, I am saying that all buying strategies are the same (good) if the funds used to invest in bitcoin are discretionary income.
On the contrary not all buying strategy are good, you spoke of lump sum strategy and DCA accumulating strategy, but you never spoke of dip buying, and I can confidently say that those investors that focus only on dip buying aren't doing it the right way, because by waiting for the dip they are going to miss a whole lot of buying opportunities that may present itself in the market, so it's not a good strategy.
The best way to invest is to use either the DCA accumulating strategy or the lumps sum strategy, then if their is a dip in the market, you may decide to buy aggressively then, only if you have the reserve funds to do so, but waiting for the dip only as a strategy is a terrible way to invest in Bitcoin.