I think the best example for why this is useful is described by david glasser at...

		eventreduce on April 16, 2020 \| parent \| context \| favorite \| on: EventReduce: An algorithm to optimize database que... I think the best example for why this is useful is described by david glasser at his talk about the oplog driver used in meteor.js https://www.youtube.com/watch?v=_dzX_LEbZyI