Scenes aren't just levels. Let's say you're making a bomb item for your game, in Godot you would probably make a bomb scene with a particle emitter and a model

Scenes aren't just levels. Let's say you're making a bomb item for your game, in Godot you would probably make a bomb scene with a particle emitter and a model and a collider. You could then use the scene editor to configure these components instead of having then all in code. Tweaking certain parameters is much faster with the UI than using code and a debugger. Imagine trying to line up a sphere collider with a model using code and a debugger, vs just dragging the handles around. The scene editor also works as an inspector, so you can fly around your scene and inspect properties and the scene graph while the game is running.