I think the main purpose of these links is to allow people to grasp the purpose of special properties itself rather than linking to an extra documentation of the given special property. To have all special properties explained here is possible too but has indeed just not been done yet. I have added a note to the page making this more obvious.
I am afraid that Property:Has component is just a plain "bin" for everything that is fed into it, so Semantic Forms was not mentioned in this respect so far. However, thank you for the pointer.