Your statement is correct, I really think the most important thing when considering investing in bitcoin is first of all having a discretionary income to invest with using the DCA Method could actually help us to invest and accumulate more on a regular basis depending on our discretionary income, definitely we might have some challenges financially so it might not be a guarantee that even if we are able to accumulate every week with a specific amount we might still face some challenges with our portfolio.
The main reason why discretionary income is important if you are opting for DCA is that for DCA we need an amount that can be large or big but we have to make sure that this amount is available every week for investing in Bitcoin. Our primary income which we get from our job salary or through business is used to meet our day to day expenditures and we cannot make sure that we save a fixed amount every week for Bitcoin. Generating discretionary income is not difficult these days because of availability of online work, all we need is a will to generate a discretionary income.
Dca strategy must not even a very big or large amount as you said i think you are mistaken lump sum to dca because it is in lump sum strategy that an investor uses large amount to buy bitcoin with your dca amount can still actually be big depending on the investor capacity and also how large his discretionary income is and also the dca can also be done either weekly or monthly not just weekly.