Not to mention that curling up with a small laptop the size of an iPad (MacBook Air 11'') is even more ergonomic because it has a built-in stand and doesn't need a cover. Close to the same weight, same size as an iPad, but a full laptop.
have you ever tried using a laptop in bed , in a similar position to if you were reading a book? It kinda sucks (yes, even the 11'' air). Tablets replace magazines, not computers (at least in the "position in which you're using it" category).
Why would you want a stand if you're going to hold it anyways?
In bed, I often lay on my side with my tablet locked to portrait orientation but it is standing horizontally with respect to the bed. This way, I don't need to support it with my hands to read, only need to use my hands when I need to scroll or pick something new to read.