Yes, the "S" enhancements changes how you can use your Iphone. Touch ID , 3D touch ... makes a huge diference .All those "S" changes can be summed with one word: Faster.
Those "S" enhancements don't fundamentally change how you can use iPhone. Whether it's 64-bit, more RAM, or Touch ID 2.0, the difference is simply "faster."
On the other hand, the major iPhone revisions tend to change how people use iPhone.
5: LTE and camera for Facetime HD and/or practical tethering
6: Apple Pay, VoLTE
7: Water resistance and telephoto lens
Touch ID you dont need to put your passcode everytime you unlock your phone , so this change how you use your phone.
3D touch is really nice .Honestly, I cant live without 3D touch . Its useful .
Touch ID 2.0 u dont even notice that u unlocked your phone ..
This faster makes a huge difference at least for ME