It's true, but I think people have a misunderstanding that if you add search / RAG to ground the LLM, the LLM won't hallucinate. When in reality the LLM can still hallucinate, just convincingly in the language of whatever PDF it retrieved.
The purpose of the system described in this post is OCR inaccuracies - it's convenient to use LLMs for OCR of PDFs because PDFs do not have standard layouts - just using the text strings extracted from the PDFs code results in incorrect paragraph/sentence sequencing.
The way they *should* have used RAG is to ensure that subsentence strings extracted via LLM appear in the PDF at all, but it appears they were just trusting the output without automated validation of the OCR.
I could be totally wrong here.
Though I imagine scenarios where the PDF is just an image (e.g. a scan of a form), and thus the validation would not work.