A good reason for Lua would be the example at the bottom of this page: https://wezfurlong.org/wezterm/config/launch.html#the-launch...
Custom settings depending on the environment you're in, here setting up PowerShell on windows only. Allowing the same flexibility through JSON/YAML would not be as easy and simple.
I don't know, IMO it would be better solved by profiles, environment specific settings (eg. settings.json + settings.windows.json), or override keys, eg:
{
"font": "xxx",
"[windows]": { // windows overrides
"font": xxx
}
}
If they want to stick with Lua I think they should allow both: write your config in JSON for the 99% of config that is easy, and allow to modify and return an updated config in Lua. TBH I just downloaded Wezterm a few minutes ago and got bored just wanting to add a Cmd+K shortcut to clear the buffer.
Wezterm apparently uses Lua so it will likely never have a UI. I don’t understand why a config file would ever need programming constructs, give me JSON or YAML, not Lua.
It sounds like Ghostty will scratch my itch.