Here's Linus Torvalds explaining it better than I could: https://youtu.be/Pzl1B7nB9Kc?t=263
And sure you can transfer your string that someone else does not consider a string using alternative mechanisms, but then you are only not doing anything wrong because you are not doing it at all for entire categories of languages. There is no integration story for these, and once one mixes with optimizations like compact strings or has multiple encodings under the hood one cannot statically annotate the appropriate type anyhow. And sadly, adapter functions won't help as well when the fundamental 'char' type backing the 'string' type is already unable to represent your language's string.
I also do not understand where the idea that a single language always lives in a single component comes from. Certainly not from npm, NuGet, Maven or DLLs.
Extended this post to provide additional relevant context. It's not a bug, it's a feature.