> I truly don't get Google's move.

Because Google wants to kill off its search engine here. It is very clear.

> I assume it's a play to test the waters for how the ad market is going to work, because as a product I really can't see why I would ever use it. Dropbox comment moment incoming?

This assumes that Google search is still a high priority for Google. With their privatized adNetwork, they are trying to get people to trust them, and abuse users via their ads. That is their business model. Google is an adCompany. It stopped being a tech company many years ago already.

Also they control the adMarket for the most part. Just look at youtube.