The idea behind the curve is mostly to bring all profitable voting behavior into the light to be scrutinized by everyone with their free downvotes.

The curve by itself is not expected to bring about honest voting practices alone. I can't see a very strong level of superlinear not favoring bid bots, even if we weren't at all concerned about voting equality, so I'm not sure why it should be considered.

The idea is to have enough free downvotes at any given time to push contentious content at least down to the point where they'll be making more curating honestly instead (buffed to 50%).

Convergent linear is meant to just prevent the ability to hide vote farming in micro spam comments relatively undetected.