@b0rk There are still cases where a system has no internet access (regardless of whether for technical, organizational, or legal reasons). Every tool should have reasonably comprehensive offline help/documentation; it could be --help (if it's complete), it could be man, it could be info, or even documentation in plain .txt — it doesn't matter, as long as I still have access to the documentation on a system cut off from the network.
Every non-trivial tool failing to do this is just deficient.
Additionally, websites (contrary to popular belief) aren't eternal. They disappear—and the more niche the tool, the more likely it is to happen. And when they go, the documentation vanishes with them.