Not even close to iPad Mini size. Don't imagine it larger than it is. Here's a comparison that should clearly illustrate how much smaller it is than a mini: https://www.dropbox.com/sh/ufzp4gowu1sa6xb/AADVfpM7--3jbq-i20B52eXOa?dl=0
Why I want a "phone" that large? First, I hardly ever use the phone part. So I really want a bigger-screen-but-still-pocketable computer that happens to also have phone functionality for the occasional times I need to take or make a call. Personally, I see this as an iPad Mini Mini- all of the great features of the iPad in a pocketable size with a bonus of full iPhone Phone functionality too. Instead of owning an iPhone AND an iPad Mini, I'm hoping this hits the ideal middle ground and kills 2 birds with one stone.
I couldn't have said it any better myself.