It depends on who you ask. Some people say we have no influence, other people blame us for every bad idea the Devs have and try to implement. It depends on the day. I will say that I did not expect to have as much influence as we have had in the last few months when I first ran.
That being said, you’re right - it is a popularity contest. But that’s what every election is.
The CSM was created after a pretty bad scandal where a Dev was a member of a major alliance, and was caught spawning in game items (BPOs) to benefit that alliance. The result was a breakdown in trust between the players and CCP, and the CSM was created to provide players with a direct voice to the developers.