iPad's hardware is already a perfectly usable general purpose computer. It is very portable, unlike your fridge, and has powerful processor and high-capacity battery, unlike your watch. The only problem preventing its use as a general purpose computer in a sense of Macbook is a lock by the manufacturer, which prevents loading a proper OS on it, and the absence of hardware specs, nothing more.
Reductio ad absurdum just to drown out the merits of the parent post. Your iPad is far more capable than those three devices. It should be able to do what the user would like to do.
And an iPad is nowhere close to the safety-critical nature of the other computers. There is no defence for its locked down nature.
So does my watch, my fridge and my car.