I agree with you, In fact, if you invest in Bitcoin in DCA, The amount of benefit it will give you, without DCA It cannot be obtained in any other way. When Bitcoin exceeds $200K - $500K in the next cycle, then DCA investors will undoubtedly benefit the most. In fact, if DCA is continued continuously in the long term, an investor can benefit more than his expectations in the future, That's why for Bitcoin investing (logn term), DCA is the best investment method.
You speak as if DCA is one very specially investment of its own but it's not, every Bitcoin investor doesn't have to use DCA before they become profitable, I am not saying that the strategy of DCA is not good, it's good but let's assume I have $1 million dollars and I invested it all at once into Bitcoin and held it for twenty years and someone else started to DCA on the same month that I invested $1m, assuming he spends $10k every year on DCAing, in 20 years, he should have spent $200k total capital, you can not still compare his profit with mind. Because of my high amount that was invested, I still stand more chance to get more profit.
Since I don't have $1m right now and I am yet a student, DCA is beneficial for me because I will definitely buy Bitcoin only when I have the capital to buy and spread it into partitions to target different buy price.
Investing $1M at once could also be regarded as lump-sum investment which is also an investment/investor strategy. Advocating for DCA doesn't make it the only strategy but it relieves investors of financial stress and external pressures. Let's assume that you eventually hit a contract that could give you $20M in a deal, there's nothing bad about investing with $1M in bitcoin at once. Imagine making $1.5M from a deal and you decide to invest $1M into bitcoin at once, it could amount to financial stress especially if you are a contract worker. With such investment, you may be forced to sell all or part sooner than you would have loved to sell it.
DCA and Discretionary income is aimed at ensuring that an investor also attend to his basic responsibility with little or no financial stress to also help prolong your life and health. While thinking about investment, also consider Life.