As a potential user, I am quite unsure as to why I would use this over something like TexStudio or even VSCode enabled with some LaTeX plugins. Could you tell me/us some pro/cons of this?
I am the co-author of a very similar application (CoCalc for LaTeX) and our landing page https://cocalc.com/doc/latex-editor.html lists many of the reasons people use it. A number of the reasons apply also to JupyterLab LaTeX, or will soon. A quick summary: realtime collaboration, having the paper you're writing and the data you're computing in the same place, having a very high-resolution history of edits, using latex in course management, using a Chromebook or other lightweight client, and zero configuration support for PythonTex and R (knitr). Note that some of these reasons for using JupyterLab or CoCalc are things that https://www.overleaf.com/ doesn't provide.