Honestly I feel like the big interoperability pitch that was put on NodeJS / javascript was just smoke and mirrors to sell various educational, PaaS, SaaS, consulting, etc. products. I see much the same for Swift.
Just an anecdote of mine: I am currently building deep learning software that can run in the browser and nodejs - using the same codebase. While I am sacrificing performance compared to Python, CPP, etc., the ease of setting it up and distributing the computation are worth it for me.