The big difference is that Google Colab runs in your web browser, whereas Moonglow lets you connect to compute in the VSCode/Cursor notebook interface. We've found a lot of people really like the code-completion in VSCode/Cursor and want to be able to access it while writing notebook code.
Colab only lets you connect to compute provided by Google. For instance, even Colab Pro doesn't offer H100s, whereas you can get that pretty easily on Runpod.