With Scala, if I want to build a distributable application, I need to bundle a JRE and the Scala library, which means that a "Hello World" installer would be around 30 MB in size. It's bad practice to assume that your user has Java installed.
With compiled languages like Go or Swift, that same application now is 2 MB or so. On top this, the application runs natively on the OS since it is compiled to LLVM.
If you're talking about the currently very experimental Scala Native, my response is that comparing such a fledgling implementation to languages built from the ground up for AOT compilation and static linking is just silly.
In Scala the language is stable, the std lib is stable and the runtime is being worked on, in Swift the language is changing heavily, the libraries are under development, but the runtime might be slightly ahead. (If one can describe reference counting as "ahead".)
With compiled languages like Go or Swift, that same application now is 2 MB or so. On top this, the application runs natively on the OS since it is compiled to LLVM.