The thing I've never understood is what's wrong with an ordinary stylus?
Its key advantage over a finger is very simple. It has a point. Not sharp enough to damage the touch-screen, but sharp enough to interact to millimeter precision. For some modes of use, an un-augmented finger is too blunt an instrument.
And its disadvantage? It gets lost.
I 'd solve this problem the same way I solve it with everyday writing implements. Make them cheap and make there be lots of them lying around. In fact with my (not-very-smart) touch-screen phone, it's a biro (with the cap on) that I use to control it most of the time, reserving the pull-out telescopic stylus for times when there's no biro to hand. The phone is supposed to be finger-operable, but I find it so much easier using a biro.
I can see that the haptic stylus might be a plus for certain minority categories of usage and user. For most of us, a biro will suffice. You can also use it to write on paper!
Mr. Biro should be proud. His invention may outlast the everyday using of paper.