What apps are document-based nowadays? 90% of people's app use is in browsers and Electron apps that end up being an agglomeration of tabs and documents. And MacOS has objectively horrible window management for apps that run multiple windows.
macOS window management is basically not managing them at all and allowing them to pile up and overlap like papers on a desk, with relevant parts of each peeking out. Exposé is there for the occasion when all windows or all app windows need to be seen. It doesn't try to micromanage them all into being maximized or tiled. Not everyone's cup of tea but it works for me.