Read my post again. The upgrade to DVR is only 99cents. Yes, I'm paying around 50 bucks a month for cable, but I'd be paying for that anyways even if I had apple-tv. So really I'm getting all the functionality of apple-tv for a 12 dollars a year and I can record/save as many tv shows as I want without an added expense.
For you then it doesn't make sense. But for those who don't want a Cable TV/DISH/DirecTV package or who want to rent to watch past episodes or missed recording episodes or even watch old series or seasons it makes perfect sense.