Speed ups for searching through a document have their utility. Reading, skimming, ctrl+f; plenty of ways to spend only cursory amount of time with a document besides an LLM, so in that sense (hallucinations aside) it's not new. But.
imo the biggest genuine productivity enhancer for LLMs is having them search shit that you provide to them. you can mitigate the hallucination issue by having it tell you where on the 500 page pdf to look to check them, and it's a much better interface than ctrl F.