Accessible pro settings
One strength of the Galaxy S8+ is the Pro settings you can access from the built-in camera. It's especially useful when taking photos in cloudy settings - with Pro enabled, the nearby islands could be captured in more detail and brightness.
Where it especially shines is special situations such as the tail-end of a sunset: this is where being able to make adjustments on the fly is crucial. Not that the iPhone 7 Plus doesn't have options: they're just not accessible via the default app. Instead you'd need to download apps such as ProCamera, which would let you tweak exposure levels as well as make full use of the RAW and HDR supported by the iPhone.
However, both do need a fair amount of reading up to understand. It'd be better if Samsung just built the Pro settings right from the main camera setup itself. Still, with the tweaks, you can take some pretty impressive photos.