[naasking]

You seem to be missing the point. Markets were and possibly still are widely considered weak-form efficient. This is a disproof of that conjecture by showing an inherent contradiction between widely believed properties, ie. P!=NP and markets are weak-form efficient, therefore at least one of them is false.

Edit: "Does P=NP imply efficiency? Not at all." This isn't even a claim of the paper. The paper is claiming the opposite, that market efficiency is true only if P=NP.