I believe the "other services" here includes Personal Intelligence, which Google is pushing very hard anytime you use their AI products directly. I would bet we'll see nudges in more and places. Basically, they want to make it happen.

To be fair, I see where they're coming from: if they're providing you (what they consider) valuable AI services, they would want to monetize it somehow, because that inference ain't free. And people won't pay for it with their money, because they've trained this generation of Internet users to pay with their attention.

I also suspect they have little choice, because they foresee that the old search modality (and with it, their prized cash cow) withering away pretty soon. Personal Intelligence may well be their next big consumer cash cow, and competitors are already swooping in to try to capture that market (especially Apple with its privacy pitch.)