For anybody that didn't see that segment, give me the 10-cent version of what decoupled lighting is.

Okay, so decoupled lighting is, literally, the lighting of particles previously was based on the tessellation of the particle, of the vertices of the particles. So to get high quality shadowing on particles, we had to rely on a much greater amount of verts and it was prohibitively expensive. We couldn't do it for such large scale effects like this. It just wasn't possible. We just wouldn't be able to afford it at all. And you just end up with poor quality, blocky shadows. What decoupled lighting gives us is a much softer, more natural looking shadowing on the particles. You can see it's picking up the light really nicely here.