What about using 3D Touch as a touch pad? The iPhone allows people to swipe through text while 3D pressing texts or other blocks.
Yeah but I assume in this instance of taller for example or scrolling a website using 3D Touch would be moribund as you would be touching the screen anyway.
Whereas if you used the fingerprint scanner (on back of device) as a mini trackpad you could scroll gallery and and websites without touching screen at all.
But regarding 3D Touch, the keyboard cursor control is my favourite use for it