>but leaves me wondering why oh why?
I suspect simply because it was just dead easy to add. Vojtech, I must believe, is a master of C++ class design. I appears that he's accumulated this powerful collection of classes like a multi-purpose modulator. Classes are like cookie cutters that produce cookie objects. Once you've got one that works, it's no work at all to produce lots of cookies. Who needs modulation in an EQ, [auto]dynamic or otherwise? Probably next to nobody - at least I'm hard pressed to think of a common use of EQ modulation. If there were, you can assume we'd see such in Pro-Q at very least, given how much FabFilter likes modulation with finesse.
But putting a Melda modulator in the EQ doesn't hurt anything efficiency-wise and it probably costs Vojtech next to nothing in extra development time, so why not? At least that's what I would assume here.