The phone, especially its keyboard, is best when I get a rhythm going. If I misspell the words, auto-complete makes up for it ... unless it substitutes something completely nonsensical instead.
The iPod is the size of a large postage stamp and is best approached with a smooth but pinpointed movement. If not I may end up with a Broadway musical when I want medieval chant.
As I've become acquainted with the Kindle, I see that it's the most sensitive, the most eager to please of all the screened instruments. Even if my index finger only hovers above the gadget, it thinks I'm ready to turn the page.
Virtuoso pianists are often said to have a "good touch." Something in the way they stroke each key creates a warmth of tone. The piano keys are not pounded, they are caressed.
I think we modern-device users are developing a skill we could use elsewhere, if we chose. I think we should all learn to play the piano.