I’m pretty sure I remember Mike saying he would get this output on film - to make it easier to archive and preserve.
In my opinion, I’m not sure if film would be easier to preserve. The main problems people cite is how video formats change and how digital media storage mediums deteriorate. Let me tackle the latter first. Film also deteriorates—-look at how hard it is to get a good film print of Star Wars. You can alleviate the digital storage problem by just copying it listlessly to new storage devices. You can even try to checksum it to make sure you’re getting an exact replica of the original copy. (You can also do the same with formats and codecs) As far as I know, that’s not possible with film. So, I think most of this as possible should be done digitally.
Of course it would (and surely has been) archived digitally. The lossless versions are probably >20TB/copy. There will always be issues with formats, though. It’s easy to think a few years and a couple operating systems down the line. But over longer periods of time, compatibility will be more difficult to ensure. The format needs to be well documented, and presumably the software should be open-sourced. None of this is to suggest that it isn’t possible or shouldn’t absolutely be done. Just that, worst case scenario, that film is always going to just be film.
An LPP would have color that outlives all of us except for Frink. Other deterioration wouldn’t be an issue for an archival print. Star Wars prints are in bad shape because they’ve been watched a million times over the decades (sometimes perhaps by people who don’t know what they’re doing with film).