That's nice. It's also nice that if the narrative needs to address topic X, I've already written words on topic X. I haven't found myself copy-paste-and-tweaking such words, because the text has to fit into a narrative, and it feels more likely for the new text to work by writing it afresh with a memory of the wiki version. matrix 
Still the existing text is useful in a "write one to throw away" sort of way.
A Spike, in XP terms.