Don’t know why it took me so long to realise this. Most Djing apps on mobile devices have a split function which converts the stereo output to 2 mono channels. So each track can be played on its own channel.
Because the OT can convert those mono signals back into stereo, you can use the OT as a DJ mixer. Or even pipe that into your regular DJ mixer and use the OT cross-fader for effects etc.
Very fun solution for digital Djing without a computer and/or expensive CDJ’s etc etc.
Could also get a cheap ipad audio interface with 2 stereo outs 
or alternatively get one of those NI controllers/interfaces the Z1 lets you use the iPad as your cdjs.
Having said that, it would be totally fun to dj with full use of scenes, resampling, and 8 effects with neighbours. Would be way better (in my opinion) to have the audio coming via thru tracks as well, rather than loading all your samples on to the OT directly.
Thanks for the inspiration:)
Or feed OT with stereo iPad signal, then loop it with OT, and mix the loop with the next track from the iPad.