Look at the required process for sharing documents via email.
The only real benefit that using word processing is ease of formatting. You can run into some formatting issues when using wiki's as your primary editing tool. One thing I've learned is that quick table editing in WikiMedia can cause troubles down the road if you want to transfer the information to Excel to allow for calculations. However, I still feel it is worth using a wiki for sharing any information.
What about you? Do you send a draft of a document around via email? Do you have 4 or more versions of it on your computer wondering if you need to keep them all? Have you ever got a large document that someone else has edited and you have no idea what they have changed? These are all reasons to use wikis. I know that online collaborative documents are getting popular and for good reason, Google Docs and Zoho are really getting popular and I use them both in addition to using wikis. They offer a little more control over the document that you are creating then a wiki, such as who can edit it.
Bob is a lawyer in Charleston and deals with the healthcare industry. I wonder how many hospitals have a wiki?
Of course in Globaloria, everything is on the wiki, so everything is already in a great collaborative format. I would love to see more of us put more of our information in wiki pages, making it easy to share and easy to collaborate.