Discoverability, a document like this makes it much easier to find features and tools you were unaware of. The Python documentation is awesome, but it doesn't provide a 30k ft overview of the language and standard library, especially when the standard lib is so comprehensive.

"Unofficial" documentation can serve needs that are neglected by the official docs, even if only by offering a different point of view. I can't speak to Python specifically, but to make an analogy, a microcontroller that I'm working with right now is documented by a 3500 page manual that requires a fair amount of expertise just to know what to look for. But a seasoned embedded dev might be just fine with that, and annoyed by anything simpler. On the other hand, I can make headway by using the Arduino API and boatloads of online documentation in the form of blogs, tutorials, StackOverflow, etc.

Likewise, nobody knows how to write technical documentation that's readable by everybody.

In the case of Python, the official docs are typically the last place where I'd look for stuff, given the quality of documents such as this cheat sheet. There's still a need for authoritative "developer" documentation, but not for me.

The diversity of Python developers, from hobbyists to pro's, justifies a similar diversity of documentation.

I can't read the entire python documentation in an hour. And having never taken a programming class or worked alongside a professional software engineer, I only know what it's occurred to me to look for. Python has lots of tools that I didn't know I needed. Probably the same us true for most people, and the only difference is what level of "cheatsheet" is appropriate.

I'm embarrassed to say I learned what generators are from this. 7 lines of code; totally unambiguous explanation. I don't even use iterators all that often, so I'm not surprised that I've never googled something that lead me to them.

personally I find online docs too bothersome. Over the years I've made an entire folder of cheatsheet org-mode files and when I work I can just hit a hotkey and grep them. Also writing and updating them actually helps memorize things