So it's 'horses for courses' then
- you shut down an American 4 or 6 with the ICO (because you can)
- you shut down a Gipsy with mag switches (because there is no leaning possible at idle since either no mixture lever - Tiger - or mixture linked to throttle - Chipmunk)
except
- you shut down Chipmunk Gipsy with the fuel cut-off toggle (mod incorporated in-Service in later released examples, presumably for a very good reason e.g. minimise raw fuel washing the bores down)