Headphones to keep you honest

This forum hosts endless debates about the relative merits of the many parameters that go into high-end audio reproduction, but I don't recall ever seeing headphones mentioned as a sort of baseline standard by means of which to judge the acoustic merits of one's system. Of course, most of us will prefer listening to speakers over listening with headphones; there's no denying that the experience headphones inevitably create of music directly input to the brain, as it were, is not "natural," even if it has its own weird solipsistic appeal. But: we also know that headphones solve many of the problems we throw a lot of money at to address in our systems: room acoustics are mooted; distortion is vanishingly low; frequency response is flat and very extended (even at the low end, although felt bass is lacking); detail is hard to match. The list goes on.

So here's my question: why not use a good pair of headphones as a tool to identify both the strong and the weak elements in one's speaker-driven system?

I recently acquired a set of HiFiMan HE1000 headphones and, using a long cable, I'm able to listen with them at my sweet spot. Plugging them directly into the discrete headphone amp of my Marantz SA8005 in order to match the volume level of my speakers, I can then directly compare the sound of my system to the nearly perfect reproduction the headphones provide. And if I want to listen just with the headphones for an extended time, I can cancel the main speakers but drive the subwoofer at a lower volume; this gives me the visceral bass that no headphone can supply, as well as enhancing the illusion that the sound is coming from in front of me (an illusion the HE1000s are better at all by themselves than any other headphone I've used).

Has anyone out there followed a similar practice? Does anyone use a good pair of headphones to identify where improvements might be made in their main system?