This is because of their consistency to keep buying when prices get cheaper.
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The power of HODL in investment combined with DCA will have a tremendous effect.
Well, the DCA includes holding. It would not make sense to buy at regular intervals only to sell after a short time.
As I have said in other threads, DCA only makes sense with premium assets, such as Bitcoin. In this case Bukele has been confident from the start that Bitcoin is such an asset and that time was going to put the price in place. The (unrealized) profits of now are a simple result of that.