If the camera never moves, it seems useless. However, in Godot, a static Camera2D serves three vital roles in a game like this:
Coordinate Centering (0,0):
Without Camera: The origin (0,0) is the top-left corner of the monitor. The center of your screen might be (960, 540). This makes vector math (like rotating a ship) annoying because you constantly have to calculate offsets.
With Camera: The camera sets (0,0) to be the exact center of the game world. If an asteroid is at (-200, 0), you know exactly where that is relative to the center.
Screen Shake (Juice):
Later, if you want the screen to shake when the player dies, you simply vibrate the Camera node. If you didn't have a camera, you would have to move the entire world (player, asteroids, background) to fake a shake.
Resolution Handling:
The Camera allows you to zoom in/out to fit different aspect ratios or to change the "scale" of the game without resizing every single sprite asset manually.