It's a lot easier to optimize the APIs underlying those scripts because there are far fewer of them in even the most complicated video games than there are comp

It's a lot easier to optimize the APIs underlying those scripts because there are far fewer of them in even the most complicated video games than there are comparable abstractions in modern OSs. And there's more motivation. People accept the slightly lower responsiveness in normal OS interactions whereas even millisecond delays in competitive games are intolerable.