These performance enhancements are for loading of textures, making it more efficient when first loading them up. You may be thinking of things like distance pop in controls for the things you mention.
We will be able to control the distance at which objects such as trash cans and NPCs appear and load in for players. These kinds of controls are there to make sure non essential things are not loaded all at once as soon as a player enters an area.
Another type of control will be user side, in graphics options there will be the ability to make certain objects such as grass render further so the player can get the best visual look if they have a powerful enough computer.