You can render from a command line if you want to render an animation or single frame. Advantages include the following: 
	 
- works with single images and animation 
		
- uses less memory than having all of Maya (UI) running 
		
- can be scripted 
		
- can be integrated into a rendering pipeline (render farms) 
		
- for Maya software rendering, you can override render settings using command flags (for other renderers, you must also write a MEL script) 
		
For more information, see 
		Command line renderer.