Note that the BRDF ignores the subsurface light transport. But for most materials, this simplification brings little errors and more efficient implementation.
I find it really cool how the physical phenomena of BRDFs translates over so elegantly in a computer program.
Specifically, every BRDF is parameterized by an inbound ray and an outbound ray, so if you are writing a computer program to simulate material, you can call the BRDF function on any material with the same arguments and get completely different results because of function overloading.
It's really interesting to read about the application irl; Pixar has published a bunch of papers discussing how they create their characters but this one in particular is pretty cool: https://graphics.pixar.com/library/PxrMaterialsCourse2017/paper.pdf
It specifically talks about modeling materials, and there's a section about how they had to layer a whole bunch of diffuse/specular BRDF's to get the realistic final look in Cars 3 (not to mention a whole other set of BRDF values to model a layer of dirt on top of the car)