IT Finesse Level:
Google Home device users in US, Canada and now UK (as of 7th March 2018 ), can use their smart speakers to make free, voice activated calls. Just say something like "OK Google, call Mum" and after a brief message about emergency calls a free internet call will be started to your mum. Well that's as long as you have "Mum" in your contacts. Follow this link for a full run-down on the Google home free cals functionality
You can call any national number by requesting Google to call a name in your Google contacts as above or by asking it to call a national business. For example saying "Call Hilltop Roti" or "Call D and C Appliance Repairs" will attempt to match a the name requested with an entry in Google's immense business directory.
Users of some forums such as hotukdeals have expressed their concerns about Google recording every conversation you have using the device. According to Google, they only record voice commands after “Ok Google” or “Hey Google”. For example, this would be recorded: “Hey Google, call Bob” or “Ok Google, hang up.” The recording stops after that phrase.
I gave it a go this morning and used the Google Home in my kitchen to call my Mum while I washed up. Despite the odd clanging of an oven tray and clattering of cutlery, we were able to have a 20 minute conversation with no drop-outs call quality problems.
In my opinion Google Home is back in the lead over Alexa which only allows Alexa to Alexa calls.