I can visualize a resulting print or slide far more effectively using an optical viewfinder image - which I have decades of experience with - than if presented with the image on what amounts to a very close, very small computer screen.
I expect most reasonably competent film photographers would be in the same boat.
Perhaps you are aiming your product idea at photographers who are only just moving to film from earlier experience with digital cameras with EVFs or nothing but live view on a screen. If so, I don't know whether that will help them with the transition to film or not - I expect it might actually impede the process.
One chooses a viewing system based on how well one uses it to visualize the result.
Histograms and the like are probably useful additions, but not if they get in the way of seeing + visualizing.
Garry Winogrand's line comes to mind:
"I photograph to see what the world looks like photographed"
Optical viewfinders seem to do a bit better job of giving most of us here a bit better of a sneak peek of the result ahead of time.