Lighting is static if its precomputed. Where its stored is just technical detail. Lightmaps, probes, voxels etc.
UE4 currently can use volumetric lightmaps(voxels) for movable objects. This system would just use same voxel based system for everything. So less shader permutations.
You can actually already have this kind of system for UE4 by forcing all objects to use volumetric lightmaps. But baking still require lightmap coordinates to be setuped.