I'm a dumdum when it comes to understanding stuff about DNS. Why is this bad, and are there any good resources for understanding how these are used by companies to extract more information about our habits?
Like controlling your phone exchange, one can either watch who you connect to, or connect you to other phones regardless of the phones you try to connect to.
So Google/Chromecast only knows what DNS lookups Chromecast makes, which changes nothing with regards to privacy or anything else. It can't watch what you're doing, it can't snoop on your web traffic, etc...