Not sure where you looked, but I just looked at the CAT II/III plated for LAX and ORD, and none of them had a DH associated with any of the CAT III approaches.
I looked at the 'Company Specific' minima page for 24R and 25L. On the actual Lido approach charts it gives minima for Cat1 and Cat2. For Cat3 it says, 'Company' and then you have to refer to the Company Specific page. I guess it's an Ops Specs thing but still curious as to why Cat3B No DH would be allowed in a company's Ops Specs for DEN and not for LAX, given that the capability exists at both airports?