Is 30FPS Enough

It depends on type of game that you want to play. It depends more on GAME that you want to play.
I have 144hz monitor, and decent pc (i5-7600 + gtx 1060 3gb) and not many new games can give me effect of enjoying full 144hz because of low-mid range specs.
Playing on 30 fps is not that bad, most popular conoles from date xxxx to 2015 were limited to 30fps. And people were fine about that!
I really recommend playing on 60 fps, because of smoothness effect, that it's giving, you really think then, that you're in the game.
That's about it!