That looks like it'd be an adjunct strategy IMO. In most cases you want to have the original source material on tap, it helps with explainability and citations.

That being said, it seems that everyone working at the state of the art is thinking about using LLMs to summarize chunks, and summarize groups of chunks in a hierarchical manner. RAPTOR (https://arxiv.org/html/2401.18059v1) was just published and is close to SoTA, and from a quick read I can already think of several directions to improve it, and that's not to brag but more to say how fertile the field is.