I'd say every comment is helpful. You never know when what somebody says, no matter how ridiculous it may sound, can trigger somebody else to make another connection. Brinstorming, I think it's called. Or spitballing, or something. A very fine group process, if you ask me.
The more the merrier, I say. Not only does discussion help arrive at the truth, but others are watching and may learn and also think of something to add. It's how we weaponized semi-autists get down.