It's fine to use photometric units as an overall scale for setting light brightnesses. However, there's a technical subtlety you should be aware of. I'll quote from a blog post I wrote on the subject last year:
With RGB images, it’s important to recognize that our display devices behave more radiometrically than photometrically. A red pixel value of 255, ...
Multi-view stereo (MVS) is the general term
given to a group of techniques that use stereo correspondence as their
main cue and use more than two images.
A quote from 'Multi-View Stereo: A Tutorial' by Yasutaka Furukawa and Carlos Hernández.
So to paraphrase: We have a set of images that is larger than two, and use them in a pairwise manner by applying ...