True, but at the same time sometimes just having a type of forum can generate discussion about a topic. Like for example how after the Viper forum was created more and more topics relating to Viper began to sprang up. There were always topics about Viper before, but nowhere near as much until after the forum was created.
As for the testing forum, though people are free to use it to test signatures and avatars and stuff it also doubles as a testing environment on the admin side too. It's mostly a matter of convenience though. It's easier to just make a test post for something you're testing instead of posting in a thread and having to think of something relevent to say. Also, some thread features that need to be tested can potentially harm nontest threads, like moving, splitting, and merging of threads.
I guess one option we could exercise would be to open up a Music and Arts forum for a given period of time, like say, two weeks, and remove it if it's unsuccessful.
From the looks of the polls it's about half and half. Then again, the numbers are so low that it's not really saying enough for either side.