Well, i would say Yes it is worth it. Why would it not? If you have the money to spare, do it, it will make you "life" as much easyer as you make it.
I mean really, you do not, you already have 2, one for gameing 1 for shows or chat, when do you really need more then that. I mean i game wow and watch series on 1 screen. But well i wish i had 2, and even more 3. As you said, one for gameing, one for shows and one for whatever, If you can afford it go for it, it will be worth it. But as many people said, multiscreen gameing is not there yet, but for multipel doing things, yeah sure