The more certain the domain, the more that is possible. If you have a document database that you trust, great. For example a support desk's knowledge base. And especially if you have an escape valve: "Did this solve your problem? If not, let's escalate this to a human."

But if you are searching the Internet, you'll find multiple answers — probably contradictory — and the next step is to ask the model to judge among them. Now you want all the intelligence you can muster. Unless you really trust the search engine, in which case yeah a small model seems great.