For many queries, Google offers more of a "ready-made" solution e.g. from a StackOverflow post or blog.
When looking at the offline documentation, I know that I am looking at a supported version (not something ancient or much newer than what is deployed in production) and that I am looking at the "authorative" answer i.e. the "real" docs not some third party comments.
When the program I am developing is expected to run correctly even in the presence of errors, it makes a lot of sense to me to consult the authorative documentation rather than "the web" which rarely covers all of the possible corner cases.
When looking at the offline documentation, I know that I am looking at a supported version (not something ancient or much newer than what is deployed in production) and that I am looking at the "authorative" answer i.e. the "real" docs not some third party comments.
When the program I am developing is expected to run correctly even in the presence of errors, it makes a lot of sense to me to consult the authorative documentation rather than "the web" which rarely covers all of the possible corner cases.