If I create a view of a table containing JSON data (or any other kind of data), I can create columns from calculations on existing fields.

I'm guessing the advantage of generated columns is that they are real columns, not computed columns like in a view. This means that if an insert doesn't work with the new generated column an error will be generated? Is that a correct understanding ?

Is this perhaps the main advantage of this feature ?

The data creation and storage options, always computed or stored on write of dependant columns seems like a possible advantage too.