One big difference between NeRFs and this technique is that a NeRF is a jumbled mess of interconnected nodes, while this is a collection of values that lives in 3D space. It's much easier to reason about and could probably be integrated fairly easily in other 3D software like editors and renderers, and probably even animated. I agree that neural nets are cool and useful, but the whole black box function approximator that represents a whole scene at once thing doesn't feel scalable or elegant.