The “curly“ stays were intended to spring the rear wheel down and keep it it contact with the road, saving the minor loss of traction over bumps. Originally they were only intended for racing.
My father had one for a short while, just after the war, he didn’t pay full price and was glad he didn’t, he said the stays were whippy and the extra forces involved often broke the seat tube just above the bracket (Hetchins were one of the few builders Reynolds released the lightest gauges of 531 to.) He sold it after a few months and bought a far more sensible bike. He also said the stays making the builder recognisable is largely a recent myth, cyclists in those days, on the whole, being far less concerned with the maker’s name.