Some games like Destiny, GTA etc are peer to peer (P2P) games. In simple terms this means every player is host. Therefore the simple ping graph used for other games does not accurately illustrate the quality of the game.
Peer ping is a bar graph of pings to each of the hosts (there maybe multiple people at a house or on a console) and shows you the minimum, average and maximum. Its probably best to pay attention to the average. To enable peer ping, simple tick peer ping above the Geo-Filter.
Below the Geo-Filter you'll see the peer ping section appear. It has a service selection combo box. The number here correlates with the services at the top of the page. For example if the second service from the left has Xbox > Xbox Live and you're playing Destiny on it. Then in the peer ping feature make sure to select Service 2.
When the game starts it will start to ping the peers. It may take short while to start but will continue to ping throughout the game.