[neonsunset]

C# is a compiled language at all levels (source into bytecode, then bytecode into machine code either JIT or AOT). V8 has JIT compilation for hot paths. As a result, JS is significantly faster than the interpreted languages like Python, Ruby and Erlang/Elixir/Gleam.

[anthk]

C and Vala curbstomp JS in speed.

[neonsunset]

C is an unserious and an unusable language when alternatives are available to you. Vala is a toy to write Gnome applications.

[anthk]

No one under GTK/Gnome uses plain C, they use Glib as a wrapper. Plain ANSI C might be 'unusable' for modern UI needs, but, as I said, just have a look on WebkitGTK4. Glib everywhere, WebkitSettings are a breeze to setup.

Vala it's a toy because Miguel de Icaza went full MS with C# since Ximian. If Vala had more support from Red Hat, Gnome 4 could support Vala as the main language for it. JS? Lua and Luajit wouldb be a better choice for Mutter scripting. If you have a look on how Luakit and Vimb behave, the difference it's almost nil.