I don’t know why you would ask Gemini to explain how Zettlr’s Markdown is supposed to work instead of asking me directly, but basically, Zettlr is an in-place preview editor. We replace each formatting char as necessary. In Zettlr’s Markdown syntax, you can, for example, also create numbered lists with task items. If we were to hide the list characters, you wouldn’t be able to tell whether a task list is based on bullet points or a numbered list. This can lead to unexpected results if you forget which is which and have undesired outputs when you export. Zettlr always prioritizes not confusing users by providing as much information as possible.
Most renderers such as the GitHub one are intended for simplicity and this can get away with simply hiding the base list items, but they have a different use case from Zettlr. Lastly, what the Gemini model confuses as well is that on GitHub Markdown is rendered into an non-editable state, whereas Zettlr keeps everything always editable at all times. When you edit GitHub Markdown, you will also always see the formatting characters, even if they are hidden when you preview the Markdown.