What is the difference between these two persistent notifications?

I use two apps which require a persistent notificaion: (1) the Pebble Smartwatch app, and Tasker. When I pull down the notification bar (see screenshot), I see both notifications. However, only the Tasker one shows an icon when the notification bar is hidden, and likewise only Tasker shows a slot on my lockscreen.

What is the difference between how these apps are showing their persistent notification? From my understanding, if an app wants to run continuously, it MUST put a persistent notification on the notification bar. But somehow the Pebble app is not requiring an icon or displaying on my lockscreen.