If a binocular is placed with the eye guards on the eyebrows, the arms do not need to lift all the weight of the instrument, only a small part. The arms mainly aid in pointing the instruments. Of course that does not make the binocular tripod-stable. But it brings a lot of freedom to view the heavens across the skies. It is a compromise between freedom of movement and stability of the instrument.
I wear glasses, I can't rest the binos on them. The glasses correct my astigmatism. Also, the 20x80s weigh 2.5 kg as opposed to 1.7 kg for the 15x70s.
On a good tripod, the added detail is enormous. The higher the magnification, the more so. Buit for extended objects, detail is not always the thing that matters most in the views.
I have the Tiltall tripod that is very good but twisting my neck to view upwards makes it hard to use them. Even with a parallelogram mount you still have to look up, which is awkward unless leaning backward in a ZGC, and then a parallelogram is hard to use when changing positions, I think.
I once built a holder for a first surface mirror at 45 degrees right in front of the lenses with the binos on the tripod, but the optical quality of the mirror was not nearly good enough.
I'll figure something out for stabilizing the binos in front of my eyes on the ZGC. The realization that I had a ZGC was an aha moment, so thanks for the message.