If they do consider gold coins (you don't know, the desinformation fog is thick), the reason could be that they expect an attack on a paper money system, consisting of a competing gang of thugs printing false notes and spread them, draining resources from the country and sending the fiat into hyperinflation. It has been done.

Minting gold coins and spread them in the IS would not work, the extra coins would be just as good as the islamic coins. Making coins that looks like gold is not easy, and can be detected by anyone.