"One of the primary goals of Steem’s reward system is to produce the best discussions on the internet"
That is taken from the whitepaper. it takes more than just a good post for the best discussions to happen, people need to engage. These metrics try to find the people on steemit that are making the best discussion happen by looking at certain metrics.
Very good. So, as you were saying to someone else, the contribution score would be something that would work in concert with, say, UA, and therefore give us all a better idea of who is potentially producing good content as well as producing the best discussions.
yes, they should be able to be used together and in isolation, it really depends on the needs. but the whole idea is as you say to give us a better idea of who is actively engaged in the best discussions