The point is to sell Swift. In the C++ example, he didn&#x27;t cast each integer to int64, but he manufactured a reason to do it in Go and Swift. Perhaps this means that Swift&#x27;s compiler optimizes that particular case almost as good as Go&#x27;s. It doesn&#x27;t matter much because it&#x27;s a single threaded useless benchmark. It&#x27;s the kind of thing that can change with a new Go or Swift release. As you know better than I, Go slowed down a small amount when the recent GC optimizations were done. Is that a reason to use Go less? No. The GC is quite amazing (and there is HTTP2 support).<p>In general, why do I care if there are slight variations in the speed of a for loop? The bottleneck in any app is the database or network access. Maintenance and readability matter to me a lot more than minuscule variations in speed.<p>As someone who programs in Go and Swift, I can tell you that Swift has some things Go doesn&#x27;t. For one, it has generics. Even still, I would likely never use it over Go on any code that runs on a server. This is due to readability and the Go standard library. I would still choose Swift over Go for iOS development. This is due to how the iOS stack is premised on object inheritance.