Today, Google announced that you'll soon be able to make calls with your Home smart speaker, assuming that you're in the US or Canada. You can call any of your contacts, along with "millions of businesses", by saying something like, "Hey Google, call Dad". Since it recognizes your voice, "you’ll reach your dad instead of just any dad."
There is a bit of an issue though. For most users, the recipient will see you as "Unknown" or "No Caller ID", which means that your phone call probably won't get answered. The only callers that this won't happen for is Google Voice and Project Fi subscribers, although Google says that it's planning to fix this issue by the end of the year, and when that happens, the caller ID will show up as your own mobile number.
The good news though is that these calls are free. You're not subscribing to any telephone network to do this, and they work over Wi-Fi.
Google also announced the Home Preview Program today, which will allow users of the smart speaker to be the first to try out new features. The company says that it's of the same quality as production updates, so if you want to get the new calling feature first, that's probably your best bet.