The cape is worn in inclement weather only, for obvious reasons. When the army switches to winter dress the greatcoat is worn. It’s not rocket science really! The cape allows protection from inclement weather during summer, so routinely shirt sleeve order ends at 1800, the CO can extend to 2100 if l remember correctly. Civilians don’t really understand discipline or army rationale. Shirt sleeve order ends at 1800 because if mosquitoes and malaria. Of course ceremonial duties are never conducted in shirtsleeves. But the terminology is used during summer time. Two inches above the elbow, the sleeve rolled to 4 inches wide precisely.
Tbh they only look bad on some guardsmen because of the length of the rifle with bayonet fixed. Otherwise the capes are well fitted and smart looking imo