Why not using the actual land line? I still have one. My 13 year old son, who has no phone, uses it and it works. I'm just curious.
Depends on the country, but landlines are no long available for new customers and the cables are actively being removed.
TinCan owner here. The issue with landlines in my experience is that they quickly become overwhelmed with spam calls. That and the ability to lock down the phone to just a few numbers is the appeal.