Rolling the opa's in the FUN's dac output stage can add or reduce clarity in different parts of the frequency range. It can also manipulate the presentation: layering, etc. This is more than any EQ could do. As far as I understand it, EQ will only adjust the overall balance of the frequency range. The rest of your post makes sense, just wanted to clarify that though.
Exactly. Cables and opamps do more than just manipulate the frequency curve. I've rolled both as well as EQ'ed for years and I can tell you that EQ'ing is *not* the same as either.