That is for long-term investment and I think it is not effective either, it would be better if we see and wait for the right price to enter even though the price of Bitcoin is always moving and different but at least there is a point where we wait for a low price in between when we have the money.
Your advice is a poor investment mentality since the new investor is investing for a long term, why should he wait till bitcoin price dips before buying when he is a new investor and has the money to buy bitcoin right away. Because he is investing for long is the main reason why he should start buying immediately using DCA since it is a strategy that allows you to keep on buying weekly or monthly irrespective of the price of bitcoin at that moment to increase your bitcoin stash bit by bit overtime.
To invest using the DCA method is quite good indeed but we also have to be able to maximize profits by entering at the right time.
There is no special time to enter the market when you are DCAing because no one can predict the price movement of bitcoin and if you keep on waiting for the right time, you might end up not buying any bitcoin at the long run because you want the market to come to your own price which mght not happen instead of you taking advantage of the price in the market
For example, right now, the price of Bitcoin is soaring, so if we already have money, it would be better to wait a few and enter/buy when the price correction has occurred.
What makes you feel that the price of bitcoin will dip again after all the dips in August and September before this current price of $65k+. What if the dip did not come, it means that you will keep on waiting and watching the price of bitcoin increasing and others are taking advantage of the market to keep on increasing their bitcoin stash. When bitcoin dipped to 52k and pumped till 63k+ with several corrections before getting to 65k+ yesterday, you didn't buy.
Any new investor that is waiting for the dip will end up sitting on the fence watching other people making profits from their bitcoin investment in future. This is why new investors should invest the moment they have the money and continue buying with DCA overtime.