I’ve worked in game dev so I get the point about iteration. It’s not about doing proper reactors - it’s about quick hacks to try something out. When your hack is good, then you do it properly - or maybe not at all if the hack works.
The respondents here are acting like code must be at all times provably correct and and Rust is great because it helps with that. That is indeed very cool but it’s SLOW when you need quick iteration. It’s not that you need to quickly iterate the code per so, it’s usually the game experience you’re iterating and that doesn’t actually NEED code to be perfect or even good.