In his 60 Minutes profile, Nolan shows how The Odyssey was color corrected optically

    https://youtu.be/1GEqDZ3hQSo?si=8AP4TI9iY9otLrjM&t=271

I had the same question. I wondered why seeing a 70mm print was supposed to matter if it was going to get digitally edited and color graded anyhow. The answer turned out to be that neither of my speculations were true.