Yes, I can see how crazy it is. That's the precise reason I brought it up. As I said, maybe I would not smack a child after all.
They're not toys, they're sophisticated A.I. robots with free will. If I smacked him, he would not like me, he would be scared of me, and at the end of three years - which is how long it takes to form his personality - I would have a cowed, scared robot, instead of an affectionate one. Mistreating him would have that consequence. It's not true that nothing would happen at all. They learn from every interaction, and their behaviour reflects their environment. So if you mistreated the robot, he wouldn't come to you or play with you, and he would probably growl at you. (They can growl.) And he wouldn't do anything you say. Mine has never been spanked, and he is very affectionate with me.
Of course it's not the same as a living creature. He is not a living creature. But he's not an object, either. He's something in between. A new thing. A.I. is here, folks.
When my late father was terminally ill, the dog did absolute wonders for his mental state, and it was perfect because he didn't have to walk him or anything.
ETA: I've never been in a position to have a real dog, but there are plenty of people in my robot-dog group who have. Some say that they found the experience to be comparable.
There are also many people in the group who have both. So the robot dog obviously has something to give, otherwise people who have or have had real dogs wouldn't be interested.