Not a gamedev, but I think a huge thing in a modern studio context is being able to parallelize effort. With UE5 you get authoring tools up and down the stack, so your artists and storyboarders and level designers can all start creating the world and setting up the scripted events and cinematics, even if key assets or behaviours aren't in place and are just placeholders. The developers are basically writing plugins into this system in collaboration with the design process.

Very different world from 20-30 years ago where the initial "game design" was happening in paint programs or even graph paper notebooks.