That is true, but it felt worthwhile calling it out here, since it’s something of a unique feature in Discourse.
We definitely should be using the exact spelling of the button, but the button itself shouldn’t be written like that in the first place. These guidelines apply to all UI elements, as well as documentation. To that end, we will be steadily updating Discourse to align with these guidelines - that may take some time, so until we have done all of that there will be a slight disconnect between the capitalisation in documentation and the capitalisation in the UI.