I have seen it, and agree it's interesting. There's one idea in there that I think is more broadly applicable - circle-like forms when the deflection angles are relatively small, and higher tension (in this case, based on ellipses) as deflections increase.
Whether these particular splines are useful for, eg, font design, I'm not yet sold :)
Whether these particular splines are useful for, eg, font design, I'm not yet sold :)