The law of comparative advantage relies on some implicit assumptions that are not likely to hold between a superintelligence and humans:

The transactions costs must be small enough not to negate the gains from trade. A superintelligence may require more resources to issue a trade request to slow thinking humans and to receive the result, while possibly letting processes idle while waiting for the result, than to just do it itself.

Your trading partner must not have the option of building a more desirable trading partner out of your component parts. A superintelligence could get more productivity of atoms arranged as an extension of itself than atoms arranged as humans. (ETA: See Nesov's comment.)