How is it not a good thing that you don't need to worry about CPU branch prediction when you're writing Javascript to POST a form to your server? In most cases

How is it not a good thing that you don't need to worry about CPU branch prediction when you're writing Javascript to POST a form to your server? In most cases you don't need to go that deep to fix performance issues. Your SPA is probably slow because your app bundle is 10mb, not because you have an inner loop that is tripping the branch predictor.