Pixel response time is a related concept to framerate but more about how long it takes a pixel to change from one color to the next. Usually measured in cycle time from grey to grey again, a low rate just means that images will be smooshy looking, have unclear boundaries, and end up with a 'motion blur' effect. So even if your mbp supports a reasonable sounding 120hz (8.33ms for a full frame sweep), some of those pixels will still be in transition when the next frame hits. At least, my take on it as a somewhat casual gamer.

It depends wildly on the type of game.

e.g. if you're playing a single player turn-based strategy game, you might be taking a few seconds between each decision & UI interaction. Some hard turns you might step away from the computer to think things through for minutes without touching the controls. 30fps for a game like that could be fine. 15-20fps might even be fine, especially if the game engine manages to avoid adding unnecessary input latency & is able to process input events at a faster rate even if the render runs at a low framerate.

If you're playing competitive FPS games, where reflexes matter, you'd want to get input, network & video latency as low as possible, within reason. Not high-frequency trading low. I have no idea at what point it stops making a competitive difference. If you have +100ms more latency than I do, I suspect that'd give me a noticeable advantage. If you have +10ms more latency than I do, I'm not sure that matters.

Dan Luu wrote an article about input latency [1] in 2017 where he measured latency by running experiments pressing a key & measuring how long it takes to see a response on the screen. New computers from 2017 would have around 70ms-170ms latency, depending on the model.

[1] https://danluu.com/input-lag/