How is a game question/thread promoting more interaction or promoting good discourse over a question that has a polling aspect to it?

Nearly all questions in Social have a polling aspect; if it can’t be Googled it is basically a question centered on opinions. However, a game question/thread by nature are even more constricting; if people went off on side conversations or introduced other variables, the thread would fall apart, so you are locked in to the construct of the game question/thread. How does that promote good discourse when to do so will destroy the thread? How game questions supposedly work better in Fluther, than those with polling aspects, and where is the proof apart from opinion which has polling aspects?