[Diapositivo]

Any kind of light bouncing around the lens before reaching the film degrades image quality, some detail must be lost. You might like the effect, or not, you might even need it, but the lost "quality" (in the sense of information) is not something that can be recreated in the darkroom.

High internal flare reduces both the contrast of the lens and the "micro-contrast" (acutance) which is one of the qualities that we perceive as sharpness.

That is only of interest to those persons, or circumstances, when you value sharpness of course.

So my answer is that it makes a difference, and that it is a difference that cannot really be compensated in the darkroom. But that said, using a low-contrast (high-flare) lens and raising contrast in the darkroom can give you the results you were looking for.