I was on a Social Media platform yesterday and what seems to be a very intelligent person was arguing the Cardano blockchain in its inherit design will not be in need of a DEX when SC are launched. His words were very technical and above my skill level. Can you folks please elaborate on that?
His simple words were "If I have ADA and want to buy native token XXX, I can simply go to XXX website and exchange there. No DEX is needed.

Question? Can you argue with or against his thoughts, and why are there DEX projects coming up?