The cost of the "discovery feature" should be considered too. In my case, the cost (being distracted/annoyed) is so high that it outweighs the benefits of using the app. But maybe this is just my problem. It's entirely possible that I'm more easily distracted than I thought. I considered myself average in that regard. When I read in this discussion how easily some people ignore it (some didn't even notice it)... maybe I should reevaluate.