I agree, I actually saw specks when viewing the Odyssee on 70mm IMAX. Sorry, but how is that "better" than any clean, digital projection? And the hoops they apparently jump through to make it work during the shoot to get to that point. Pure nostalgia hysteria.
Digital is not clean. Noise exists whether molecular or voltage on a sensor.
The clean you are used to is likely a compression or digital filter result.