Every time a movie comes out on DVD, the studio usually adds bonus features such as deleted scenes. By studying these deleted scenes, you can see why these scenes were cut.
In many cases, scenes are cut because they duplicate information that other scenes already provide. That just shows the importance of knowing your scenes so you don’t repeat information twice.
In this “Captain Marvel” example, you can see another reason why this scene might have gotten cut. It’s boring.
Scenes need to show conflict and reveal information through action. In this deleted “Captain Marvel” scene, there’s little conflict and information is told strictly through dialogue. When you reveal information through dialogue, it’s boring and lifeless.
For your own screenplay, make sure you don’t reveal information twice and make sure every scene contains some type of conflict. This conflict can be simple but it needs to be there. Without conflict, you simply have people talking with no sense of direction.
Also make sure you reveal information through action so the audience learns information at the same time the main characters do. When you just have main characters doing nothing but talking, it creates a dull scene, as this deleted “Captain Marvel” scene clearly demonstrates.
Scenes need to move your story forward, not hold it back. Study deleted scenes and you’ll see how not to write a screenplay. Ideally, your own screenplay won’t have scenes that can’t be used because they’re dull, redundant, or both.