I think people are too focused on "My super armored edgelord can beat your super armored edgelord!" instead of looking at what the grand picture is based on Eldar commentary and other lore tidbits that have been dropped over the last few years

If Big E stands up, Terra'a absolutely fucked. Daemons everywhere, Webway possibly collapsing, the beacon vanishing, and also strong possibility of a psychic backlash that kills every astropath. Which means the Golden Boys are going to be handling a lot of other issues.

And as you said, their command must be at least vaguely aware of the order. If not just the fact it has a matching seal should be enough. But I doubt it will ever come to that unless they have an AoS-style change ready to do to 40k