A Wikis unique feature is that other users can contribute to them and add material, typically in an easy way. (Easy compared to creating your own website, at least.)
Now, Wikipedia might not always qualify as the best source for a definition, but in case of Wikis, I think it is a very good authority.![]()
I'm well aware of the definition of a wiki. If it stretches your imagination too much to understand the comparison, fine, ignore it.
A well configured wiki, or other piece of content management software could have been used to provide the same (and likely better) functionality for a lot less development time.