Because we built the application, we know what it does. The help site is generated from that — so it does not drift, because nobody is maintaining it by hand.
There is a quiet failure that happens to every product: features get built, shipped, and then used by almost nobody, because the only people who knew they existed were the ones who built them. The usual fix is documentation, written separately, by someone with other priorities, and stale within two releases. We take a different route. The help centre is produced from the application itself and published on your domain, the changelog writes itself from what actually shipped, your customers get told, and your support chatbot answers from the same content without anyone being involved.