Embeddings: What they are and why they matter
You can indeed use Retrieval-Augmented Generation or question and answering. Is this not what "Uploading a pdf" or Advanced Data Analytics do in ChatGPT Plus under the hood? Another point of finetuning a model is to caputure the behaviour and underlying "reasoning" that comes with it. The token limit is another reason why RAG might not be enough if you want more than just Q&A with an LLM.