Discipline plays a vital role in anything that we are doing, especially on achieving a goal to be a successful investor in a long time bitcoin journey. This is because you will be on the roller coaster for 4-6yrs and above. If you are not discipline to be consistent in using DCA approach as a beginner on your bitcoin journey, you will not be able to build up your bitcoin portfolio to a great height, because you will invest reluctantly.
What you said @Troytech is right but to only some certain investors which are the poor and average class that have more expenses to take care of, but discipline applies to all category of investors. Take example of a rich guy MrX, that has every resources to take advantage of having a significant amount of bitcoin in his portfolio, but because he is not discipline and feel he has everything because he is rich and chose to invest in bitcoin using DCA method but he hardly meet up with this because he lacks discipline. On the other hand MrY is not rich but have a means of income which after all calculations done, he can take care of his monthly expenses and emergency funds. He still could DCA regularly, and due to discipline, he was consistent with increasing his bitcoin portfolio for 15yrs. MrY will have more bitcoin than MrX, during the same duration of 15yrs. Sometimes, before you know it MrY bitcoin accumulation can bring him closer to the level of riches of MrX, because of compounding profit.
However, if a rich guy like MrX, let's say MrZ is disciplined in his bitcoin investment journey and invested on the same duration of 15yrs with MrY, he will have more bitcoin in his portfolio than MrY. This is because he will use his wealth to take advantage of investing aggressively in bitcoin using all three method of bitcoin accumulation strategy because other of his investment can serve as his emergency and reserve funds, so there is no cause for alarm.
Drawing facts from all what you said, Discipline in the mind of a person is what authenticates and gives reference as a true Bitcoin lover that is willing to become a true Bitcoin holder.
Dcaing for a 4-6 years period especially when purchasing weekly, may look too easy to keep up but it takes only a disciplined mind to keep it going notwithstanding other factors that may hinder the accumulation process.
Anyone thinking that there is any 100% certainty about Bitcoin price prediction is probably new to the business because the experienced people know that there is no such things as 100% certainty. We can use past data to guess the future and it could be right or wrong, this is what we are expected to bear in mind to be able to make informed decision and not act in a manner or take actions that may lead to regrets and tears.
Even though we do not know what the future will be for Bitcoin, it is our expectations that at some point in the future it will become more valuable than it is today, the reason we are buying and holding it while keeping open mind to various possibilities that might unfold. It is obvious that Bitcoin has become more popular, more accepted and looking more promising than it was in the past and these are indicators that it is worth owning.
Rightly said, everything about Bitcoin is not of certainty but of pasts stats and mere predictions (some may not know the difference between assumption and prediction, we say prediction when there is a strong reckoned of much data that the possibility of not happening is lesser due to past occurrence and facts while assumption on the other is just saying stuffs out of guess due to the intention of wanting to see that happen) that may tend to occur and possibility of not happening as well. The stats are there to rely on, the adoption of Bitcoin is getting really good, its adoption in countries and most companies is evidence of a better future ahead. Those who bought right from time were in the same dilemma of which in years to come its adoption and price will skyrocket and yet all this happened and that's one start we rely on for the progress of Bitcoin accumulation.