It also says that both of them are limited by tmux, which I use 100% of the time in the terminal. The real problem is when you run Vim in tmux and start to scroll in a large file that you notice that Terminal.app does not cut it. It lags badly. In Alacritty its silky smooth.

And yes, scrolling with j/k for longer periods may be an anti-pattern in Vim and yada yada... I scroll in Vim, and in Alacritty its smooth, in Terminal.app its sluggish.

Word of caution when reviewing this report: it doesn't take into account vblank period. If you hit a key just after a monitor refresh, you're not going to see it until the next refresh cycle which is typically up to 16ms later. This study is concerned with how long it takes to update the frame buffer rather than time-to-visible which is difficult to measure.

That said, there are plans[1] to reduce Alacritty's input latency. Though, I personally use it as a daily driver and have never felt that there was a noticeable input lag.

Once that lands, Alacritty will have similar latency to Terminal.app _and also have_ a 60 Hz refresh rate (the "smooth" feeling), low CPU usage, and much higher throughput.

[1]: https://github.com/jwilm/alacritty/issues/673