It's incredibly fast, has the features you would want like tabs/splits, maintains comprehensive compatibility, and is written cleanly in Zig. What's not to like?
Most terminal emulators are in fact slow and they can be a huge bottleneck if you run complex TUIs or workloads that print a lot of output.
Ever written a program that was extremely slow only for it to run instantly after removing your debug print statements? That's because your terminal is slow.
Fast terminal emulators already exist, but they notably refused to add tabs/splits and overall tended to be quite janky. Ghostty merging these features may not be the most groundbreaking innovation, but a high quality piece of software that can drop-in replace something you use daily with some cool improvements is something to be excited about to me. :-)