The TitleKey extension is only for use in the search field, not Wikilinks.
If you have a Wikilink to a page with:
Random Wiki Page wrote:Waze uses an [[editing rank]] system to determine your ability to change the map.
This works fine to link to the actual page that is titled [[Editing rank]].
However, if there is a page like [[Your Rank and Points]], if you entered [[your rank and points]] it would fail because that page name is different due to the cap change on the second and subsequent words. Only the initial cap can be ignored and still get to the correct page with a Wikilink. In this example you would need to put in the link [[Your Rank and Points|your rank and points]] to get lower case in the sentence displayed to users.