The use case in that example is for ephemeral notebooks used for demos. It's also good for running notebooks for temporary classroom use. When backends are spa

The use case in that example is for ephemeral notebooks used for demos. It's also good for running notebooks for temporary classroom use. When backends are spawned, there is a period of time that they remain alive without a connection. By default, it's 5 minutes. So if you accidentally close a tab, but open it back within 5 minutes, the kernel is still there.