Problem with next storage band is that its a max of 64GB. With cards you can have as many as you need and swap them in and out as needed so its essentially unlimited.
As for Apple TV yeah its great for at home (I use an Acer Revo personally as you don't need to worry about format), but what if somewhere else that doesn't have Apple TV..Friends & Family, work, etc. No option without spending more $ and getting the dongle.
Not that its any competition against an iPad on a complete package basis, but as a comparison, you can buy a $170 tablet from China right now that has native HDMI out (not mini-HDMI) with the ability to push 3D (2160p).