It seems a little odd that the grandparent comment was about arguments from authority, but here we are talking about Grothendieck's work in pure math and Eliezer's on methods of rationality. Because the thing is, in neither area can an appeal to authority work. Regardless of how much G, or how much scholarship and expertise they have acquired, they both have to "win" by actually convincing ordinary people with their arguments rather than overawing them with their authority.

On the other hand, when advocating anarchist political positions or prioritizing existential risks, authority helps. Trouble is, neither math skill nor {whatever it is that EY does so well} qualifies as a credential for the needed kind of authority.