There's also a lot of difference in mocap vs traditional animation. When characters are animated they follow certain principles that aren't realistic but result in pleasant and entertaining movement. Real humans and creatures don't behave this way.

So when animators are working on live action films they have to carefully balance the adherence to these principles with the realism of the scene.

There's obviously liberties taken (the mocap data is always cleaned up before being applied to a character) but think of the difference between an explosion in a Michael Bay film vs one caught on someone's camera in real life.