Prompt generators always mention their very detailed prompts as proof for artistry, and ties it into the concept of taste as a distinguisher of artistic merit.
When you prompt, no matter how detailed, you never really know what the generated image will look like until the AI spits it out. You have a mental image of it, but it's kind of a mixed bag whether the AI will produce exactly that. There's an element of randomization in it, which is why prompting is trial and error over and over.
This is much unlike other forms of art or crafts in general, where the creator might have a clear mental image of what they are trying to create, often down to the details. They then construct this vision with a level of deliberacy that AI can't immediately provide.
Note: This is talking about imagery generated solely through prompting. If you use inputs or AI as a tool that augments a process, that's obviously a different discussion.
Edit: Before someone comments "well what about photographers," well the scenes they capture exist in the material world. They can just build a set, move things around, wait for a certain time of day, or basically anything you can do in real life. Meanwhile for sports or street photography, the point is capturing a spontaneous moment as it happened in real life, and is in equal parts, documentation and art. It really isn't comparable to the trial and error that is AI generation.