It's a service they sell to eg DuckDuckGo and ecosia. I think the og bing is just there because they still think Google may fall out of favour one day. Oh and they offer a corp version spiced up with internal results from SharePoint.
I think they also make money from people that don't know the difference and use it because, for instance, it's the default in Edge when you search from the URL bar.
The normal consumer accessible one in contrast routinely gives me broken incomplete output
Idk MS you’re not gonna win with a chatbot that doesn’t chat complete stuff