If you read my post very well you would have understood that I didn't say I prefer the bot accumulation to manual accumulation rather what I said was that the bot has setting, it can be changed or altered but that's still another stress and a long process that some people won't have this time so the manual still remains the most convenient and simple way of accumulating Bitcoin because, like you said one can easily adjust whenever there's a shift or change in our discretionary income or needs.
Our needs are not the same every month or every week, so with the change in needs, the amount of our discretionary money can also change regularly. With this regularly changing discretionary money, the manual investment method is effective, if we want to do DCA with the automatic investment method, then we must have a lot of discretionary money. Suppose, if you do DCA weekly, you must have enough discretionary money to do DCA for a few weeks. The automatic DCA system is effective only for those who have a lot of discretionary money. For low-income people or ordinary people, manual DCA is still more effective. In this case, I agree with you.
You have raised some important points. In particular, discretionary income is not the same every month or week. In some weeks, expenses, bills, medical, loans, school fees or other expenses may increase. So if someone sets up automatic weekly DCA without considering their cash flow and discretionary income, there is a possibility that they may actually buy BTC with money that was not actually their discretionary income.
Not everyone is required to have the same strategy. But I personally think that manual DCA may be more realistic for those who are low-income earners or those whose income comes irregularly.