In a traditional LaTeX workflow, you would edit the LaTeX source in a text editor, compile the document every now and then, and check the effects of your changes in the DVI viewer. In Compositor, the DVI viewer is the document editor - you type directly in the rendered document, and every keystroke is immediately reflected. The source editing and compilation steps are completely eliminated from the workflow. This not just gives you immediate visual feedback, it should also save you quite some time previously spent on compilation runs.
No more tedious compilation runs. Compositor typesets and renders your LaTeX document on every single keystroke.
Compositor's WYSIWYG user interface offers a document outline, inspector panels, and other conveniences you'd expect from a modern word processor.
The app comes with its own LaTeX distribution built right in. No need to install any additional software just to get going. This is LaTeX without entry barriers.
There will be situations where you want direct access to the underlying LaTeX source. Pressing Ctrl+S will open an inline source editor showing the LaTeX source behind the document region you're currently working on (often this will be the current paragraph). This should allow for a smooth migration experience to this new paradigm, even with commands or environments for which there is no dedicated graphical inspector (yet).
If your document uses LaTeX packages not bundled with the app, they are automatically downloaded from CTAN. And if you are using packages not available on CTAN, you can still provide them to the app easily.
Compositor reads and writes regular, plain text .tex files. This means it's compatible with your existing LaTeX documents. Also, there's no lock-in of any kind - you can switch between Compositor and other tools at any time, since there's no proprietary file format involved.