So do you need for images, photos, spreadsheets, PDF files, websites, schematics, board layouts, databases, mechanical drawings and models, neural network models, music masters, audio tracks, video footage and any other file format used by professionals.
Better yet, all the formats I mentioned are raw text and not even binary. And all have well developed tools for editing.
But isn’t that a good enough use case?
Almost nobody bothers to put proper formatting, diagrams, tables, formulas, references etc in their source code. At best we get ASCII approximations.
To see some examples of what it could be like look at Mathematica, Jupyter, literate programming, and org-babel.