Accessibility enables the visually impaired (or those who can’t find their reading classes or can't focus due to painkillers) to "read" their iphone. (Settings-General-Accessibility). VoiceOver is tricky to use at first, but it will read your iPhone to you – each icon, text, email, etc.
This feature is also helpful to use your iPhone in your pocket - with earbuds in – if pulling the iPhone out is inappropriate.