@rewireIT I think you have it right, the only confusion is over how the meter behaves.
Yes, it would function exactly the same without the switch and the 'N' connection to meter in the sense that all final circuits would 'work'. It's equivalent to doing safe isolation and testing L to CPC bar to confirm polarity.
The point is that the meter (if digital) wont record anything without a return current path. The switch is providing a return current path. So when the switch is on, the meter electronics fire up and records some usage.