User blog comment:DaNASCAT/Technical Update: November 27, 2012/@comment-1280533-20121129104617/@comment-5028213-20121201160758

Well, search does find help pages on your own wiki. CC help pages aren't on your own wiki, though. They are on CC.

Analogously, if you search in MediaWiki namespace, you will only find local pages as well.

That's why Help:Contents and CC help pages need to have thorough linkage and Help:Index should be kept up to date. The point of Global Help is to show help pages on page call, like, through direct links.