Personally, my main reason to prefer Kitty over Terminal.app are (I believe Ghostty support all of them as well, so looking forward to try it out):
- “Kitty Keyboard Protocol” means that a TUI app can detect all keybindings. For example, if you install kkp.el in Emacs, then Emacs running in a terminal will pick up ctrl+shift keys, super keys, etc. on par with a GUI app. I believe NeoVim supports this out of the box now as well, so if you ever felt like binding Cmd+S to :w you now can.
- “Kitty Graphics Protocol” means that I can let e.g. Matplotlib show images inside a terminal, even over SSH connections. If you’re annoyed at pop-up GUI windows, or struggling with viewing remote images often, this is a nice workaround. There are even attempts at making terminal PDF viewers (like termpdf.py); IMO that’s a game changer, even though the app itself is still in a “proof of concept” stage IMO.
- Terminal splits. If you work a lot in a terminal, it’s nice to be able to full-screen a terminal and view many different shells or processes side-by-side. Last I checked, Terminal.app just doesn’t have this feature. Sure, you could use multiple windows or a multiplexer like tmux, but that comes with different trade-offs; for example, a native terminal offers smooth scrolling with a trackpad whereas tmux doesn’t. Personally, I use tmux remotely, but stopped using it locally.
- I see a lot of people mention 24-bit colors as a main reason to not use Terminal.app. For me, I’m actually pretending that I have a 16-color terminal, because I’m tired of having to theme every command-line utility individually, I’d rather they all just respect my 16 chosen colors instead. The only exception is my editor, just because there are unfortunately few good 16-color themes these days, so I instead change my terminal program to be consistent with my editor theme and then let every other TUI utility believe the terminal only supports 16 colors to match.