A supplier agreement runs to fourteen pages, a tender document to sixty, an insurance policy to something nobody has ever read end to end. Feeding these into a tool and asking what they say is genuinely valuable, and it is one of the few applications where the time saved is obvious and immediate.
The value depends on what the summary is for. Used as an index - what is in here, where are the sections about payment, does this document mention penalties at all - it is excellent, and it turns an unreadable document into a navigable one. Used as a substitute, so that a decision is made on the summary without anyone opening the original, it quietly changes what you are relying on: not the document, but a description of the document produced by something that cannot be asked to stand behind it.
The specific weakness is that summaries are built to be representative, and the things that hurt you in a contract are rarely representative. A single sentence creating an automatic renewal, a clause capping liability at an unhelpful figure, a notice period expressed in an unusual way - these are small, local and easy to leave out of a fair summary of the whole. The summary is not wrong. It is a summary, and the clause that costs you money is precisely the kind of detail summarising is designed to drop.
That suggests a better way to ask. Rather than requesting an overview, ask the document targeted questions and require it to quote: what does this say about ending the agreement, quote the exact wording; are there any automatic renewals; what happens if we pay late; list every deadline with the clause number. Answers that come with the original text attached can be checked against the page in seconds, and demanding a quotation turns a claim you have to trust into one you can verify.
Then read the parts that matter. For most business documents that is a small fraction - the money, the dates, the exit, and anything the other side drafted specifically for this deal rather than lifted from a template. The tool's real contribution is telling you which pages those are, which turns a document nobody would have read into a document somebody read the important half of. That is a large improvement over the honest alternative, which in most small businesses is signing it unread.