I'm old enough to remember when "Google" was something that ended conversations. People — myself included — would literally say "Google it," the facts would be located, and that was that. Now that Google wants to be the conversation, I'm worried there will no longer be a bias-free source of information for the masses.
This is all new, so I may be a bit hyperbolic, but the reason OpenAI introducing ads bothers me is the implicit (or even explicit) bias that can be smuggled into a chat in ways that simply aren't possible when you're just clicking through to an external source. There are all kinds of implications to Google no longer being that source of truth, even by default. Maybe this has quietly been the case for a long time, but this feels like the final move — pushing their ad bias (i.e., whoever paid the most) into a conversational system, where dark patterns are far easier to implement and much harder to detect.
One answer to this might be domain-specific agents — narrower, accountable, ideally something you (or your community) actually run. But even then it all falls back on trust: you being a good-faith actor, and others trusting that you are one. Which is to say, we're back to the same problem, just at a smaller scale.