You could shoot better pictures. The new 6s phones have a 12-megapixel rear-facing iSight camera, which Apple says will create brighter and clearer stills and video. This is an improvement over the 8-megapixel rear camera in the iPhone 6. ( The limitations of that camera can be clearly seen in the washed-out details of images.)
front-facing ( or “selfie”) camera also gets an upgrade with the iPhone 6s. The new phones ship with a 5-megapixel front-facing camera, a decided improvement over the 1.2-megapixel camera in the iPhone 6.