M.P.
My brother used a similar thing with his dogs. He quit using it after a short time. For me the major drawback is that all that urine and feces is deposited in a container. Yes, the fake grass covers it up but the urine and feces has to go somewhere. You then have to clean the container. Yuck!
My brother walks his dogs and because they are outside and cannot go back in they do their business. If you are just putting him out the door then close the door and force him to stay outside for awhile.