Like jockspark I too remember the 14th and although not a reg afaik it was frowned upon to have a neutral at the switch unless needed.
We used to do pubs in the 80s and it was the norm to fit commercial switchbanks under the dist board and use double pole grid switches feeding the circuits.
Sometimes there was about 24 outgoing neutrals on maybe 6 or more lighting circuits.
I remember a new guy did not understand and tried to 3 plate all the circuits at the fittings instead and nearly lost his job.
As you say though, in houses, with mainly ceiling rose 3 plate, there was no need to wire it that way back then.
Not doing domestic much I have not come across many neutrals at switches, but can see how it could assist as I have come across a few now boxed in ceiling roses, where downlights have been put in.
What is normal, to do the whole house the same,or just the rooms that benefit, and wire the other rooms in the more conventional loop in ceiling rose.
some of my walls are only 3 inch breeze so I would imagine it gets a bit busy with 3cables a connecter and a dimmer.
If this method is as common as it sounds , I suppose the sleeving now is even more essential and perhaps twin brown may become more popular.