I think to some extent it depends on what you see apps as on a device like the AppleTV. To me the big potential draw of app on a TV is access to other content

I think to some extent it depends on what you see apps as on a device like the AppleTV. To me the big potential draw of app on a TV is access to other content streams that Apple hasn't negotiated contracts with. So while on my old AppleTV I can watch iTunes content, Netflix and HBO, a smaller content provider can build and submit an app. I can also get apps to stream local content. For this kind of use using a MacBook or iPad is not a very good substitute. On the other hand, if you are looking at filling the position of a Wii or XBox, and you game solo, than the laptop or iPad might have material advantages over a TV app, especially if you always play solo.