From what I\'ve seen the tag is ignored when hosting a WCF service in IIS. I understand that when self-hosting this is required but is this harmful or even used when opera
As you have guessed, the baseAddresses element is completely ignored when hosting in IIS. The service's base address is determined by the web site & virtual directory into which your wcf service is placed.
Even when self-hosting, baseAddresses is not required. It is merely a convenience that avoids you having to enter a full address for each endpoint. If it is present, the endpoints can have relative addresses (relative to the base address, that is).