I'm working on a top-down shooter akin to DoDonPachi, Ikaruga, etc. The camera movement through the world is handled automatically with the player able to move inside of the camera's visible region.

Along the way, enemies are scripted to spawn at particular points along the path. While this sounds straightforward, I could see two ways to define these points:

1. Camera's position: 'trigger' spawning as the camera passes by the points
2. Time along path: "30 seconds in, spawn 2 enemies"

In both cases, the camera-relative positions would be defined as well as the behavior of the enemy.

The way I see it, the way you define these points will directly affect how the 'level editor', or what have you, will work.

Would there be any benefits of one approach over the other?