Can you explain? I don't understand it either. I use iTerm2 on a modern mac; does that mean I don't have the performance problems being addressed by kitty and alacritty?
It is useful with some badly written build systems that think they have to write every invocation of gcc to stdout. Like every badly written Makefile out there. Or `cat myapp/log/yesterday.log`.
You can work around both but it's clunky. And also it's a thing that's not a must have, just a nice(r) to have.