JupyterLite would probably be my go-to for working on a script or just trying out some Python or something like that. It looks like it'd be way less friction than getting Jupyter running locally, especially if you don’t use Python often.
Pyground is specifically written for a use case I wanted to optimise: to get data from a file on your local machine into a structured Python variable fast. I think with Jupyterlite you’d have to upload the file and then write your own code to read it/parse timestamps, which is just boilerplate. So if you're trying to do something like that and don't need anything else that JupyterLite offers then pyground might get you there faster. JupyterLite is way more flexible though.
Also you can use pyground to load the data, then do `import pickle; pickle.dumps(data)` in pyground, copy the output and then do `import pickle; data = pickle.loads(<copied output>)` in JupyterLite and you'll have the loaded data variable way faster than writing that code yourself and all the flexibility of JupyterLite :)