You could think of WYSIWYG like being able to edit preview mode directly without typing markdown symbols.
There is a spectrum of WYSIWYG editors. Some completely hide the source markup (Microsoft Word, Google Docs). Others will show you the markup when a line is active (Typora, Roam). The plan for Obsidian is to be more like Typora.
https://forum.obsidian.md/t/a-wysiwym-typora-like-editing-mode/1953