I think people in the comments are assigning "DCA" to either (3) or (4) below, but having different assumptions about what the alternative might be...

1. Have a pile of cash to burn and invest it immediately, to maximize time in market

2. Have a pile of cash and sit on it to "time" a later lump sum entry to the market

3. Have a pile of cash and invest it incrementally for some ramped entry to the market

4. Have recurring income and invest it immediately as it becomes available

5. Have recurring income and save/buffer it up to revisit the alternatives (1)-(3)

6. Use credit to obtain a pile of cash ahead of income and revisit the alternatives (1)-(3)

I consider DCA to be equal notional amount purchases of an asset at a fixed period (weekly, monthly, annually etc.). That's it really. Wherever the money comes from.