The iPad was widely criticised at first for its Noddy home screen; there were no software or hardware concessions made regarding multitasking or task-switching. But the result is something my two-year-olds can easily navigate, and which really doesn’t need a manual.
To which I’d add that most apps I’ve downloaded that have required reference to any sort of instructions have rapidly found themselves in the disused folder.
So there’s the fact that your 2 year old and your Gran can use it. Sure it’s got the grunt of a desktop machine from a decade ago but you can get apps that do more than my first (Pentium 100 Windows 95) PC ever did*, and more intuitively. Without instructions. The software-becomes-the-device.
*I still get the heebees thinking about how I struggled to get Cubase on that old PC to do more than any four-track cassette could have at the time..