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.