The linked post on their website has a few more sentences, but no hard promises yet...

Thanks to our diligent community who pointed out a series of recent marketing images may have included elements of generative AI, we are rethinking our process of how we work with vendors for our marketing creative.

We already made clear that we require artists, writers, and creatives contributing to the Magic TCG to refrain from using AI generative tools to create final Magic products. What’s now apparent is that we need to update the way we work with vendors on creative beyond our products—like marketing images we use on social media—to make sure that we’re supporting the amazing human ingenuity that is so important to Magic. Along with so many others, we also want to get better at understanding whether and how AI is used in the creative process. We believe everyone benefits from more transparency and better disclosure. We can’t promise to be perfect in such a fast-evolving space, especially with generative AI becoming standard in tools such as Photoshop, but our aim is to always come down on the side of human made art and artists.