I may have written it someplace else but this API would place constraints on our lighting implementation that may be hard to maintain in the future.
Basically currently lighting is computed on CPU so we could implement this kind of API but going forward we plan to migrate to a GPU-only solution, which would require a completely separate implementation for this API to avoid GPU readback.
So while it’s not too hard to implement this right now, going forward this API may become problematic to support.