65mm =/= VistaVision

Vista Vision is 35mm turned on its side. 65mm is the exact same thing as 70mm, but without an audio track (the negative that's run through the camera is 65mm, the prints that are released add 5mm for audio, which is where we get 70mm).

So 35mm is to VistaVision as 65/70mm is to IMAX.

VistaVision was originally just a widescreen filming format Paramount invented to compete with anamorphic cinematography. (Note that VistaVision does NOT produce an aspect ratio comparable to anamorphic cinematography, it's closer to 1.85:1 than 2.39:1.) Paramount and VistaVision lost out to anamorphic lenses.

ILM, when making Star Wars, decided to revive the format for the visual effects shots. The reason for this was that, on top of the incredibly fine-grained 35mm film stocks then in existence, the VistaVision process was designed to minimize grain even when film stock was much, much grainier than it was in 1976. Most films at the time (Close Encounters) used 65mm for the same reason, but VistaVision, being that it was 35mm turned on its side, was much cheaper to use than 65mm.

It worked so well that I believe most films with heavy optical effects after that used VistaVision until digital technology replaced optical compositing (this hasn't happened 100% completely yet, but it's damned close).

But Close Encounters and Blade Runner definitely used 65mm for their opticals, not VistaVision, so an 8K scan makes sense. An 8K scan of 35mm turned on its side seems kind of pointless to me - I'd be happy with the whole of Star Wars, including the opticals, being scanned at 4K. Which, sadly, doesn't seem likely.