Having/needing a second screen is not only not very popular, I don't think it is here. There are very few examples where it makes any sense playing a single player game.
In video game past, playing games in the same room used to be extremely popular. While people still do it today, it happens A LOT less, defaulting to multiplayer over the internet. With this being true, a second screen doesn't really make sense for multiplayer either.
I see it simply as companies trying to find something new to do.
Yup, I guess it hows how it is implemented imo being able to on separate screens on the same console in the same room would have been nice (if you could stand the noise

) i.e Player One has one 21inch screen and Player two has the 2nd 21inch screen so on.
True, I miss the n64 days playing mario kart, mario tennis etc (gamecube version was not so good.. imo it was to kiddified), playing time splitters 4 players on the Ps2.. lol endless fun. Oh No Mercy on the n64 - one ladder match lasted pretty much a day and half, my cousin's and I only stopped playing cos the console overheated and froze LOL. These days games just don't have that appeal it becomes stale after a few matches. Then again I guess you could call that growing up lol.
General rule of thumb, if you don't take risks you can not innovate - something may catch on where as it might just disappear quicker than a ice cube in a desert.