Bing Chat often searches the web and bases its response on what it finds. This tends to find more accurate information on TeXmacs than what ChatGPT finds and synthesizes from its internal knowledge.
Generally speaking, Bing Chat often bases its responses on a few web pages while ChatGPT often bases its responses on a lot more.
For many topics, I prefer the way ChatGPT works. But for TeXmacs, Bing Chat users will get more accurate info.