Anything to boost performance even if slightly is a bonus.
say you have 50-100 props in an area that the player would never touch, thats 50 less objects that need to be bothered for collision and physics. Should be a somewhat slight gain but a gain none the less eh.
Was also looking at visibility and shadows.
Default everything casts and receives shadows, looking at which objects you can get away with turning these settings to off must also help.
As to visibility, there are 4 settings of World and Map, World, Map, None. You can look at turning many objects such as small props to world only so they are not rendered in the default map system that comes with HE. Again maybe another small boost.