What are the software differences between a standard and plus version of an iPhone? (e.g. 7 vs 7+) Apple is pretty good at documenting the hardware differences between iPhone models such as the iPhone 7 and the iPhone 7 Plus. 

However, I know there are software differences as well that don't seem to be documented. When making my decision to purchase one over the other, I want to consider these differences as well.
iPhone X Plus vs. iPhone X features:


Horizontal rotation on home screen, which can speed up folder browsing.
Uses regular horizontal size class when device is rotated to landscape orientation. This allows apps such as Notes to display the list of notes on the left hand side and the note details on the right-hand side in a split pane view.


iPhone 7 Plus vs. iPhone 7 features:


Bokeh effect as @tetsujin mentioned.