Not at all. Especially when it is limited to specific models, adds extra cost and will never be widely supported by the market.
Welcome to computing. And this is not the forum to complain about extra cost--this forum thrives on extra cost. Or have you not looked at the case modding subforum?
By the way, what do you mean by "never be widely supported by the market"? It's not as if games need to be coded to take advantage of G-Sync, ala Mantle or TrueAudio. You get an Nvidia GPU, you plug it into a G-Sync display via Displayport 1.2, and you're set for the usable life of your display. There is no additional support needed.