Let's be realistic, though; this 21:9 screen is a pretty dumb idea. What's going to make your productivity go up is increasing the 768 rows, not giving you 1792 columns. Can you see more text in Word? No, since having two pages side by side is pretty silly when you can't fit whole pages vertically on the screen. Can you fit more lines of code in your IDE of choice? Again, no.
A 1792x768 display has nearly exactly the same pixel density as a 1366x768 screen. There's no way I'd take the former with a glossy finish over the latter with a matte finish, and even if everything else were equal, I don't know why I'd take a heavier laptop just to gain nearly useless screen real estate.