I’ve been reading ‘Marx’s Theory of Money: Modern Appraisals’ after there was some debate on here about the role of commodity money in Marx’s value theory.
@__gio and @StoryPegasus rightly pointed out there are many places where Marx insists on the necessity of commodity money, however I am inclined to agree with @criticofpolecon and @ygzgzot that it isn’t essential to the logic of his value theory when further developed.