Why Would I Care About Apps Being Used Around Me?

Continuing to pick apart Apple's WWDC keynote (there was a lot there, so this may go once for a while) another one of the 'features' Apple announced was the ability to see which apps are in use in your vicinity. 

Whilst I could see a positive intention in most of what was disclosed in the Keynote I'm somewhat bemused by this.

Am I really supposed to care what apps a bunch of strangers around me are using?

Its pretty much the equivalent of walking through a supermarket looking in everybody else's trolley and expecting to be able to select your own shopping based on what they're buying. 

I don't know anybody who does this. 

And I know some strange people. 

It's a completely pointless feature. I'd be much more interested to see which apps my friends have installed, at least there I'll have a frame of reference for that information. 

What I'm not overly clear about is whether this is at the expense of the App Store Genius. That would be a shame if that were the case.