I don't get all the fuss about dual lense? What's the point? The s8 camera is as good if not better than the iPhone dual lense one and its better than all cheaper dual lense ones.
If you're this much into photography just get a proper camera instead, don't try to play photographer with a smartphone. It's like rendering and editing videos on a phone - sure, you can do it, but why?
All this fuss for a less hassle panorama shot?
Well I already own 2 DSLRs and a film camera but as they say the best camera is the one that's on you at the time so it's nice to have a comprehensive package available right in your pocket. Whole point of this being the next flagship is that this hopefully won't be a cheaper dual lens solution. Iphone 7 Plus and LG G6 have shown that dual cameras can finally be done right when there isn't too much disparity between the sensors.
Apart from the rather well done depth of field effects right "out the box", it can deliver an optical zoom sort to speak so long as the secondary sensor is up to scratch (fingers crossed we soon see identical sensors) as well as the obvious choice of FOV that you'd want for the shot. Depending on the software and how well implemented it is, it could also be used to capture more detail and improve light sensitivity.
That and flagships are all about pushing the envelope and while it's a fantastic and still arguably best smartphone camera, S8 upgrade this year was merely in the software department.