There are plenty of things you can say that are career limiting moves if attributed to an individual at a particular company. Eg. if an OpenAI employee says that ChatGPT is negatively impacting the education of children, it gets recorded, and then used in a hit piece against the company, that could go poorly. Or a Facebook employee speaking frankly about the negative impacts of social media, as another example.

With Chatham House Rules you don't have to worry about a gotcha quote getting pulled out of context or used as a statement against interest.