More about the article:
One of the best parts of touch based interfaces is they can change with context and can be customized/improved/fixed for the cost of changing the software. No need to ship a physical 2.0 for your POS when you want to change the button layout.
Also, with these blades, are you expected to carry around more than one and swap them out based on the activity? Then use the onscreen keyboard when you need to do any text input?
The thing is a computer. It has a USB port. One can attach whatever input devices they want. The only difference about a blade is that this doubles as a screen cover. In the medical and fast food examples he gives, the machines are stationary (and you probably want them to stay that way).
I'm all for dedicated input devices or customized interfaces to make jobs easier, but that's hardly a new idea.