Generative art posts are being posted from time to time on HN for years. (eg. There are many "This X does not exist" posts)

But recently it is booming. The reason is not related to DALL·E, but Stable Diffusion.

Stable Diffusion is 1) open sourced 2) the model is small and easy enough to run on people's computer. As a result, it can embed in a lot of tools and services, so people are getting excited and start building ecosystem and business around it. When people can create art without effort, how to streamline the creative process and dealing with giant amount of arts are going to be the problems that worth solving.

As for use cases, I can see it either replacing a lot of artists or being one of the most important tool for artists, or both. Also, it might flood the Internet with its creations in the following years so be prepared.