In reply to user123.

The security argument is largely a moot point, only administrators see the code editor and administrators by definition can do all kinds of things to their installation that are secure or insecure - like installing plugins that they haven't inspected. Pros that are handing off sites to their clients can very easily create separate roles or hide the area altogether.

I rarely use the code editor, but it does come in handy when I want to explore some plugin code to do some code quality inspection or do some preliminary debugging inspections.

I like that the code editor is there because it might be the first step for some users to get interested on a code level. It's an open invitation to learn and signals that WordPress is something anyone can start coding for.

But somewhere down the road it is going to be rather nice to be able to code without having to install separate tools on a machine. There would need to be some sandboxing functionality to prevent against crashes and the like, but it's a worthy long term goal in which little steps that polish up the current experience are small, useful stepping stones. From plugging in some lines that remove or add functionality via action hooks and filters, to perhaps doing more serious theme stuff. But right now, just getting better readability of the code of plugins and themes is valuable in and of itself.

I don't think people fully appreciate the different ways that WordPress welcomes people to start playing with the platform and how that benefits the entire user base. Many theme developers, plugin developers and contributors start their WordPress journey with small steps probing how easy it might be to implement some customisation. That journey might start in the built-in code editor and why not.