This seems like a silly argument, Why even bother with a Youtube or Netflix app on the iPhone then.
Well watching a 16:9 Movies on iPhone Plus Models or iPhone X is too Small... If u c0mpare.
iPhone 5/5S/SE = 6.67 Square inch (Extremely Small like a toy, only use as an iPod Touch, SMS, Calling)
iPhone 6/7/8 = 9.43 Square inch (Very Small like a toy, Minimum for light games)
iPhone Plus = 12.91 Square inch (Still small for several movies, recommended for gaming)
iPhone X = 12.70 Sqi (Absolutely Best for gaming, it's more handy than iPad But still small for movies
iPad Mini 2/3/4 = 22.44 Sqi (Most Minimum Size for Watching 1 hour movie) 1.75 Times bigger.
iPad 9.7" = 33.32 Sqi about 3 Times bigger than biggest iPhone LOL HAHAHA
iPad 10.5" = 39 Sqi on a 16:9 movies best replacement for laptop on watching movies.
iPad 12.9" = 60 Sqi Completely replaces Television, or flat curved tv
Don't ever bother to watch 2.35:1 or climax on iPhone 6/7/8 Plus models those 12.9 square inch will be shrink down to 9 square inch only.. and that is unbelievable small. iPads are still acceptable to watch 2.35:1 they are still 17-51 Square inch still bigger than actual iPhone Screen