Yeah the lump sum approach s more profitable, but not everyone can afford to buy 1 BTC or more at a go, that's why people opt for the DCA approach. The DCA may not be as profitable as the lump sum approach, but I think it is better to crawl towards your goal than sit and wait for your goal to come to you.
You got it right. Both DCA and Lump sum are profitable though Lump sum is more lucrative then DCA but it requires huge capital which is not manageable by everyone. If you dont have huge money rather have small money then better to invest in Bitcoin in DCA manner. Following are results of investing 10$ weekly into Bitcoin for five years.
https://dcacryptocalculator.com/bitcoin
For those who cannot afford to buy large amounts of Bitcoins, it is very easy to invest in Bitcoins using the Dollar Cost Averaging method. But if you invest in this way, I think you should spend your investment journey for a long time ie your investment journey should be at least four years. With dollar cost averaging method we start our bitcoin investment with very small amount of money and if we don't hold long term the invested bitcoins with this small amount of money we will fail to reach our desired goal.
https://dcacryptocalculator.com/bitcoin is best tool where you can go and see the results of DCA. Bitcoin is for long term no matter you choose DCA or Lump Sum. You can win occasionally if you invest for short term but real success is in long term investment.