Is there a downside? I’m confused.

Yes. They are making other search engines less useful through what is functionally an exclusivity deal. They are also relying on Reddit to function as useful results since they ruined google search over the past few years.

This is bad for anyone who thinks we should be able to search the internet without being locked into google.

I'm excited for this to start triggering anti-trust legislation

It obviously should, but it won’t, because the US is a capitalist dictatorship masquerading as a democracy. The oligarchy own the government, and the regulators.