The TV is curved so that, with the larger size, you can't tell you're being ripped off!
Honestly though, is there a real benefit? It seems like marketing to me.
it keeps the screen from becoming distorted when you view it off to the side. The bigger the screen the larger the difference it makes. Pretty much every movie theater screen is actually curved like this, but that is because with projection it takes longer for the light to reach the edges than it does the center, which can also distort the image.
Honestly though, is there a real benefit? It seems like marketing to me.