The physics of light is relatively simple. Blender wants to look photorealistic, so cycles (a branched path tracer, commonly known as a ray tracer) almost perfectly models how light works. That means these emergent properties just work.

It wouldn't work under a rasteriser (Blender has one, called Eevee) as those operate using a complex series of approximations of reality that are more difficult to create but run far faster. But because Cycles (slower, but more realistic) operates by mimicking how light works this kind of thing is entirely possible.

Well, that's the best part of it: the underlying physics model is really easy!

A pinhole camera requires zero additional physics, just a simulation of light rays passing through a small hole. A lens just requires Snell's Law - which is pretty much trivial. Adding dispersion is just a matter of using a formula instead of a constant for the refractive index of the lens, and doing the raytracing using random wavelengths instead of a single "composite" one.

Raytracers capable of doing this are implemented in a few hundred lines of code as a toy project. The difficult part is getting it to render quickly - and of course modeling the scene properly.

raytracing rendering moved to physics based rendering a while ago: the core idea is to approximate the physics of light as accurately as can reasonably be made fast. It's not like it's solving a wave equation directly, it's using a statistical sampling of a model of how light interacts with different interfaces between mediums. This is basically the easiest way to get photorealistic renders: the human brain is very good at noticing when your scene has non-physical lighting (not in a 'ahah, the specular highlights violate conservation of energy' way, but in a 'this looks fake' way).

(this approach was started by some researchers who basically said 'well, let's make a simple scene for real and measure everything and make our render look identical' https://en.wikipedia.org/wiki/Cornell_box )