Not quite, the advantage is that you can give it any documents you want to search even ones that aren't available to google or wikipedia. But I think otherwise

Not quite, the advantage is that you can give it any documents you want to search even ones that aren't available to google or wikipedia. But I think otherwise that is essentially what is proposed here. The nice part is that since you know which documents got looked up when forumlating the answer you can also provide those as part of the output to the user so they can then go check the source data to confirm what was stated by the LLM.