It is currently possibly to view the relative effort scores of other premium subscribers on the website, activity by activity. However, I very rarely use the website (and suspect the same is true for many other users) so, despite my wife and I being premium subscribers for over a year now, we didn't even know this was even possible until yesterday. 

My idea is simply to make this functionality available on the android / iOS app as well, so that a greater proportion of users will be aware of it and able to easily make use of it.