As far as I know "F-curve" is just a term that refers to the graphing of a function (a "function curve"). It does not refer to a specific type of function, curve or interpolation (e.g. spline, or the more specific bezier), only to the representation of the function as a visually graphed curve, generally in an editable form. In other words no, F-curves are not "more flexible" - that is largely a meaningless statement. Perhaps "F-curves" *as implemented in these applications* have an advantage, but that is really down to implementation approach rather than implementation *type*.
In any case as far as I understand the implementation of e.g. Maya, it is a fairly standard approach and one we would likely handle similarly.
- Oshyan