i think that minecraft stores the generated data along with modifications nowadays, instead of the neat little format you describe, because generating this frequently is usually very difficult for the computer. im not completely sure though.
There would be not much practical use for it I think, but in theory it should be possible to "compress" a Minecraft world by figuring out the delta between the original generated state and the current state, and then for each chunk either saving the delta or the the full chunk, whatever is smaller.