This example demonstrates a simple use case.
When you bind to a signal, you can extract values from it using computed signals. Consider a scenario where you bind to an event from a web component.
Instead of writing $someValueToExtract = evt.detail.someKeyToExtract; $anotherValueToExtract = evt.detail.someOtherKeyToExtract;, you can simply write $someValueToExtract = evt.detail;. Then, define a computed signal for each value you want to extract using simple expressions.
If you can derrive values from the signal, it is probably better to just use the declerative approach and define a computed signal for each value you want to extract. That said, in many cases if you can do this, it should probably just be done on the server side.