I think it comes down to whether if one decides to mostly stream content (videos/music) or have it stored locally. The camera capability of large 4K videos is also a consideration. I personally split my media/documents between devices (Macbook, iPad and iPhone) and have some on iCloud (including photos) for seamless access of those between devices.
Of course, it is one’s decision but for finding reasons, while 1TB might sound overkill, it is a great purchase for the long run. Also, as a youtuber stated, this year’s camera and storage upgrade seems to be eye candy for those in the area of ‘iPhone-only’ content creation. There are some great YouTube channels with iPhone-only created content.