30 is enough for old games though I even play diablo 2 at 60, 60 minimum at least for "new" games. As long as I can play games smoothly I won't care about FPS.

I've never met anyone who would "prefer" 30FPS over 60. So I'll answer the question slightly differently.

If I am playing a game which is mostly static, like Baldur's Gate series or Civilization type strategy games , or the world map of Total War games, I prefer look over FPS. So I could tolerate 30 FPS and max the graphical settings.

However, whenever I am playing a game with constant action, Like Elder Scroll Series (Skyrim, Oblivion, Morrowind), Fallout 3, 4 or New Vegas, or the "battle" scenes of Total War series, I stick to 60FPS, and lower everything and anything to achieve that.

I mean if you're playing at 60 and drop to 30 you're gonna feel it. Dropping from 120 to 80 or so is less obvious because of the higher frames, but still noticeable. What g-sync helps with framerate wise is the lack of v-sync causing frame timing issues and stutter. So if you shoot for a steady 60fps, but have drops to 55-59 or whatever, it's barely noticeable. If you were using v-sync on a 60hz monitor, it would be very noticeable (and in double-buffered games you'd drop to 30fps).

That sounds great. I can't wait to get a good g-sync monitor with higher frames.

I'm ok with playing in 30 or 60 fps but if it is lower than 30 then no, I don't play those games.

For me, it depends on the game I am playing. But I want a stable framerate while gaming that is why I sometimes lock it 30 if my laptop cannot maintain a stable 60 fps.

As for the 60 fps, I did watch videos from youtube (dark souls series). There is a significant difference.

30fps is just unacceptable, 60+ is mandatory for dexterity games.