I am a long-time user of iPhone related technologies. I started developing in Objective-C in 1986. In 1994 I wrote the landmark article "Why I need Objective-C". Much of what I talked about there has come to pass. Sadly due to copyright law it is not available on the web. If copyright law in your location allows, you can now access a copy at Sci-hub. For many years, I published the Openstep Newsletter which covered Steven Jobs previous company NeXT Inc.
I wrote two iPhone apps, TouchTexting and TextFaster. TouchTexting is a keyboard for the blind. It has a transparent adhesive plastic sheet with braille dots on it, and an associated software keyboard that offers audio feedback. The user experience is brilliant, the brain integrates audio and tactile information much better than I could have imagined. But for blind users it required a jailbreak, and sighted users would use it while driving, leading to car accidents and law suits, so it was pulled from the market. You can see an early video here. With practice, much faster typing speeds are possible.