I’m using the Relay with my 10 year old when I go out (the grocery store, for example) and he stays home.
In the good ol’ days, we all had landline phones at home, so I could call home from another phone. Now I don’t have one of those, and I don’t want my son on the devices when I’m gone.
Because of our set-up with devices and internet access, previously I had to leave the wifi on so he could use his iPad to Skype if I wanted to be able to communicate with him while I was out. With Relay, I can use ethernet cables only and keep him off the devices when I’m not home to supervise.