I am not a human rights lawyer, although I have some background in working with international human rights. What I have been told is that for people to launch a case, such as you're suggesting, they have to spend the first part of their time in court establishing that their problem is like a disability or that it fits under a disability, whereas, if protection were listed in the Canadian Human Rights Act, they wouldn’t have to go through that stage of demonstrating that it's like some other protected right—it would be more direct.
I still think that the more important aspect is the declarative aspect, so that there's no confusion in Canada about whether something is or is not protected. If it's listed, it is protected.