There is nothing wrong using the lump sum strategy if the money is there it won't trigger any financial stress if the income is available there are rich people who are using the lump sum strategy and also the DCA strategy poor people may also decide to lump sum if probably they won a lottery or unexpected huge amount of money came there way he or she may decide to lump sum without them selling there bitcoin holding since they will still be using the DCA strategy.
But it is better they use DCA than to buy at once even if the money is there. Bitcoin price always fluctuate and if we buy at once using a large money and the price is down a lot, we can be difficult to buy back Bitcoin. But if we can steady to use the same amount of money and allocate the money by our capability, that will help us to have the money and prepare for the next down time. No, I disagree on what you are trying to say here, what's the point splitting the money to buy bit by bit when the money is available?
I am quite aware that the DCA accumulating strategy is the best way to accumulate Bitcoin, but it makes no sense if you have like $1k that you are not going to need in a very long time, but your dca budget is like $100 weekly, instead of you to use it all the $1k to buy at once, you will Start splitting it bit by bit just to make it look as if you are DCAing, who are you trying to impress by doing that?
Do not forget that we are still in the early days of Bitcoin, so it's still very cheap compared to how much it might get up to in the future, so seizing any buying opportunity is the best accumulating strategy too me, once the funds is available, just buy, because now is the best time to buy, not later or tomorrow.