Slap in a pair of external microphones into the lightning port and you have a pretty good field recorder with a touch screen and rechargeable battery.

Or load AUM, plug it into an audio interface with a camera connector and you have a digital mixer.

Or load Garage Band and you have a Daw in your pocket.

Setup OpenBubbles! You can iMessage from your Android.

iOS is to iPhones what Windows is to PCs

Put another OS on it and use it for many more years

(though I don't know the status of jailbreak or alternate OSes for iPhones as my last one was a 3G and Cydia was a thriving ecosystem then)