>>6567NovelAI generates images using stable diffusion, but they charge you for the service. You can even download the novelai model for yourself and use it in stable diffusion and it works without issue.
Since most people are capable of running stable diffusion locally, and since paperspace and colab have much better rates for usage, there really is no reason to use novelai.
Well, unless you like the simplicity, or you like the text gen, that is.
You also get the benefit of being able to use whatever model you want (like a bbw model- novelai can't do good fats and its furry model is trash)