@leocg Several reasons (from my personal experience at least):
- From my experience forums often do a rather poor job of preventing duplicates.
- Forums can be intimidating / too much of a hassle to new users / people that have hardly used a forum
- A forum has not the necessary features to determine actual user demand and therefore can only somewhat help to prioritise tasks
- Forums often require someone to actually write something, leaving out the large amount of lurkers on the internet
- The search is most of the times not as good
Whilst forums might be better for discussing things, when it comes to uncomplicated feedback, Uservoice (or a similar system) are far superior.
A lot of tech-giants use it. Microsoft uses it for almost every single one of their products (though they started implementing their own version of such a system in windows, namely the "feedback hub" or something along those lines): OneDrive, Xbox, Xbox Music, Visual Studio, Cortana.
OneDrive: https://onedrive.uservoice.com/forums/262982-onedrive
Adobe uses it for their new experience design application. And for the services I have used it has been quite great.
Adobe XD: https://adobexd.uservoice.com