Why get 1TB local storage?
You use it as the all-around pocket camera for photo and video... You use it to shoot non-pro/pro movies... You download videos from sites like YouTube for offline access, download music from services like Spotify, again for offline access... You use it as alternative to a portable external drive... You download so many high performance demanding games... You use it as a pocket computer to edit videos that you have shot using the same device... And many others...
But for all the possible reasons of getting one, can you afford it? Are you willing to go all in for that one device?