Because if Google sees this as a "red alert", it doesn't seem to be so laughable.
Even if Google can easily offer the same , and even superior functionality, it's much harder to cram ads into a chat conversation.
Even more so if competitors can offer comparable functionality.
Edit: To clarify, because this was mentioned multiple times:
There are two aspects why this might be bad for Google:
There are lot's of ways to monetize a chat bot, many of which would probably be even more effective than current ads, because they would feel more organic and thus more trustworthy.
But they would be highly misleading, and I would very much hope for regulators to quickly step in and require a clear indication that a suggestion was paid for. There are already quite strict rules around product placement in the EU, and this is definitely worse.
Sure, having to announce what is an ad is just the status quo. But I believe that would be a lot more off-putting in an "organic" conversation.
Secondly, Google benefits a lot from people clicking on links which then lead to sites that show more Google ads. A more guided and effective "chat search" experience would probably cut out a lot of those ad impressions.
Third: Google has enjoyed a very dominant position in terms of market capture and technology lead. A new technology always has the potential to upset the balance and significantly weaken the current leader, because there are now younger, leaner and more agile competitors.