1. Python doc has full up to date documentation for everything shipped with the standard library (which dwarfs PHPs grab bag of globally scoped functions)
2. The comments in PHP documentation are frequently out of date, misleading, or flat out wrong. Among the people I work with (who are working on PHP web apps, full time) everybody routinely advises the PHP noobs to ignore the comments.
3. The standard library functions shipped with most languages don't require a full page with multiple examples to explain how they work.
Don't get me wrong, the documentation for PHP is excellent, but it's a small win for a language that has so many real --language level-- issues.