It makes your development workflow smooth enough that you have the time and energy to do stuff like all the bullet points listed in https://news.ycombinator.com/item?id=46437289

Not being slow - they compile straight to bytecode, they aren't interpreted, and have aggressive, opinionated optimizations baked in by default, so it's even faster than compiled c (under default conditions.)

Contrasted with python, which is interpreted, has a clunky runtime, minimal optimizations, and all sorts of choices that result in slow, redundant, and also slow, performance.

The price for performance is safety checks, redundancy, how badly wrong things can go, and so on.

A good compromise is luajit - you get some of the same aggressive optimizations, but in an interpreted language, with better-than-c performance but interpreted language convenience, access to low level things that can explode just as spectacularly as with zig or c, but also a beautiful language.