As mentioned above, pretty much no benefits (apart from not needing to deploy it).
In reality a lot of "cons". Example: Depending how you set office up with things like templates etc, I change the default template to Pink with yellow spots, oh look 10,000 users have spotty backgrounds

(Yes this depends if you redirect templates locally, blah blah, but just an easy example).
How do users install things like addons they want? (For example our SIMs manager uses one for data import/export to another statistics site)
When I was referring to licenses it's the age old, I want 10 office, I buy 10 licenses. I put office on server, I now have "insert computer numbers" potential users I need to license, unless you're restricting who is using it etc, which then kind of defeats point to installing on server, or you run the risk of having unlicensed users etc etc.
Steve