You try to take a photo of a painting you love. You cannot quite get straight in front of it (crowds, reflections, just not very accurate or patient).
Now just take that photo without any worries and press a single button to straighten it.
Then you can save it to your camera roll or share it straight away.
Also, what about using your phone as a photocopier?
Results always look a bit amateur?
Use Set it Straight to get a perfectly straightened and cropped image. I sometimes get awful shadows from my hand and phone when I try to photocopy with the phone. Now this is no problem as I can take the photo from the side, press the Set it Straight button and get a perfect copy. As good as any photocopier.