From my point of view (an user) is hard to tell since I don't know
what these new curve types offer or what can I gain by using them. I have basic knowledge of them but I don't know what's the advantage of having more than one, care to explain?
I think FontLab has a way to edit different curve types. PostScript fonts are cubic while TrueType are quadratic. Maybe the free Fontforge has support for both too? last I checked it let you export fonts in both formats. However, font editors are one of a kind since you are editing one type of curve *or* the other, you can't mix both (maybe I'm wrong and native file formats support this (FontLab has support for Spiro curves too, how does it store them?). I need to know if this will have a "one thing or the other" treatment --i.e.:if the user sets this exclusively for each document or not.
If all the types will be editable at the same time on the canvas --like it's done now with bezier and spiro paths--, it might be worth checking 3D and CAD apps like Maya, 3D Studio Max or Autocad, since some of them support various types of curves (like bezier and nurbs, but I'm not sure if the case is the same here).
Regards.