[gaius]

It can log that you went somewhere that Google could not otherwise track you. And not just websites; mail, SSH, anything else. I'll wager a fair few people's attempts to avoid tracking for certain activities, clearing cookies, private mode, whatever, has been thwarted because they forgot they'd set this up.

[TheSpiceIsLife]

I just want to clear here: a DNS server can't track that you visited a site, only that you request a specific record for a host name.

Is that technically correct?

It stands to reason the average internet user probably then made a visited that IP.

[gaius]

Yes, that is correct. Google use every means possible to track you wherever you go. If that can't get your exact activity, they at least get something.