I used to think like that: "Oh, I don't need more than 60fps. Who the hell need 120fps or 240fps?"
And then I got my SC15 laptop with 120hz and G-Sync. Blew my mind.
And then I also got my 240hz monitor w/ G-Sync for my desktop.
G-Sync w/ high framerates is amazing. Totally different experience. I couldn't believe how much better and smoother gameplay is, in all fronts. No input lag, no stutters, no slow-downs, no graphical tears, no adjustments need to be made when playing - it's gaming perfection with amazing butter smooth performance, pretty much.
So, here's why: games can still take nasty hits or have input lag, even w/ 60fps without G-Sync or FreeSync. If you take a hit, you'll notice it; especially if it drops to 30fps in a scene. I notice it when it hits from say 60fps down to 50fps - as you get a slow-down, a stutter, a hitch, something. It makes you adjust for the framerate, in the way you play; you got to slow it down a bit.
V-Sync's issue is it goes along w/ the monitor's limit, not the graphics card - so you can still get stutters and input lag. Input lag is the pits, as it can screw up your gameplay and make it feel way more janky - and with Fallout 4, this is one of the biggest issues w/ that game. Fallout 4 is definitely a game that....needs less jank, in its combat/gameplay.
Even w/ 60fps capped on Fallout 4 (it's the hard-coded limit w/ that game) with G-Sync - this game is finally not hitting input lag, stutters, and any of that non-sense. Thank God the game isn't taking any major hits here, as you likely will notice it, even w/ G-Sync b/c you'd still be in the under 60fps range...which is what many people do not see past: 60fps.
Having 90fps will ensure when you get slapped back to 60fps on a nasty hit, you feel nothing. This is the advantage of high framerates. Higher the framerate, the better...b/c when you take nasty hits, if you remain above 60fps (which has a better chance w/ higher framerates), you see or feel nothing. This is the key. You don't have to adjust to the stutter, the slow-down, or anything - b/c it won't happen. Why won't it happen? A lot of people, they likely won't see or feel anything past 60fps, 90fps, or 120fps (depends on the person); it's going so fast, most won't be able to process it w/ their mind - so this is the best way to smooth all of the other non-sense out (input lag, stuttering, slow-downs, having to adjust to lower framerates b/c of a wicked dip in framerate, etc).
When you have high framerates, this really matters most for action-packed games w/ intense scenes and a lot of stuff going on. If there's tons of explosions, special effects, fog, God-rays, violence, action, objects, enemies, AI, people jumping online, and anything happening on-screen - expect a hit of some kind. It's inevitable with all this going on. Think of competitive games like Overwatch and fast-paced games like COD games - where there's tons of stuff happening, which is likely always going to give you a big hit, no matter what.
This is something every gamers should experience for themselves.
It's the only way you'll notice the difference, is to experience it yourself. Gamers should need and want higher framerates (yes, even if it's 90hz tops on a monitor) and adaptive sync tech (that's G-sync on Nvidia cards and Freesync on AMD cards paired w/ a 90hz+ monitor) just to get rid of the annoyances of input lag, stutters, slow-downs, adjustments, graphical tearing, and all of the non-sense.
