One is that the “ad” links in #bingchat aren’t as clearly distinguished from regular search results as they are in a non-chat search engine format. (There’s a label, but it’s small and hard to see.)
Another is that Microsoft didn’t have ads in Bing Chat for the first six months and just sort of quietly snuck them in with these barely visible labels. People who have been using Bing Chat for a while may not realize that they’re there.