Do you have some basis for these assertions? Personally I agree with the GP but it's personal anecdata only. I would never consider using tags (or a sock drawer) and in my experience working with others with collaboration tools that use tags, there might be one person who is keen in them but they are never widely used. I think this backs up the GPs point that yes, some may find it useful, but it's not necessarily a "must have" that the majority are looking for, or even would use if it was splashed in their faces.