Judging by Persuasiveness

My meta-debating position is pretty simple. I think debates should be judged based on how persuasive teams are. Persuasiveness is how far their arguments would persuade a perfectly rational average informed voter.

One thing I notice many people do is judge debates according to things like role fulfillment or engagement. There are roughly two categories of explanation I've heard for this and I agree with neither

Good does not equal perfect. A speech with a great deal of engagement can still be worse than one without any if the purely constructive speech has very persuasive argumentation. Likewise, excellent role-fulfillment and delivery do not always coincide with persuasive argumentation. In short, I don't see the need to use proxies at all when we can simply judge by persuasiveness directly. The only reason to use such proxies seems to be if you value things like engagement separate from persuasiveness.

If you value anything other than persuasiveness in debating, let's call whatever it is X, then you should be okay with the following scenario. Team A is overall slightly more persuasive than team B, but team B is more X than team A so team B wins. To me, this  seems wrong. If it seems wrong to you too, you likely shouldn't believe that anything other than persuasiveness matters. If it seems okay to you, to really go into why I have this intuition would require an explanation of why I think we value debating, which I'll go into another time.