What is the purpose of this column, does vanilla intends to use this or just an empty space for plugin developers to save and make their own functionality? Or maybe I introduced it from other plugins?
Vanillas CommentModel and DiscussionModel has methods getUserScore and setUserScore and the default theme shows the Score as "x points". Although it is not used here, I think it might be used by one of Vanillas closed source plugins.
But if you like to implement something like that I would use Score column.