Correction: AI content can be great, when the prompter (artist) puts in enough effort. In the end it's just a tool that allows you to create content. But since the output created with AI is good enough for most social media content - that is forgotten after 24 hours - most creators simply don't invest enough effort in it to make it great.
Here's a great example of an AI video that shows how it can help artists bring their ideas to life without access to a production studio: