There surely is some advantage in terms of having bitcoin prices coming down while investing and/or alternatively to just remain flat for long periods of time while the BTC accumulation is continuing to take place.
I surely will admit that it can also be painful to have extended periods that our BTC holdings are not in profits and/or they are failing/refusing to go up in value... We can end up getting anxious and then making various kind of mistakes trying to outsmart the market, yet if we continue to stay focused on accumulating bitcoin and/or holding (if in doubt?) then there seems to be good chances that at some point our bitcoin holdings will recover. and at least get our holdings back into some kind of a green situation rather than a red situation.
And, yeah, even though guys feel good in the start when their bitcoin holdings are going up in value, those price rises still might be throwing them off of their abilities to focus on continuing to persistently accumulate bitcoin rather than starting to hold at times that it is not necessary to hold and/or to hold back on the level of their buys because they believe that the price might drop.. and then the drop might not end up happening.
I know you have outlined plenty of examples how long term accumulation can play out, but those who are interested in investing, should familiarize themselves with some examples. If the goal is to invest long term, then having a look at some past examples can be very helpful when it is about how downswings in bitcoin's price can play in the investors' favor.
It feels good to see bitcoin going up from your very investment and then with every further investment you decide to make. But those who have been accumulating for at least several years will describe the effect of investing in bitcoin all the way down when it crashed in price and then keep investing all the way up again when the vey first investments recover their losses while maybe the second half of your investments already generates profit and you see that momentum keeps going.
I think every time these topics are brought up, it comes down again and again to time in the market, and of course to reasonably considered investment sizes. But this is intermingled to some degree as unreasonably high investments will probably force you to liquidate at times when the plan or hope was to keep growing your holdings. Time + capacity to absorb unexpected obligations.