warden
Subscriber
One reason to use FF...back in the days of film, there are a significant number of accessories made to precisely position a 135 slide afixed to the camera body with a specific length of tube so that it could be duplicated precisely at 1:1 onto a duplicating camera.
I have not checked to see if today you can find a product that holds slides precisely afixed to a APS-C dSLR for 1:1.6 reproduction of FF film slide
Nikon made one of those adapters for a recent digital full frame camera too, but unfortunately they have not made one for medium format film yet and that’s my main digitizing goal.