Works very well too for any kind of validation or encoding. Anything that accepts input from the outside world can accept a string. And then everything else in the app can work with a "SafeString" and the only way to create a safe string is to send a string through a string escape function (or whatever makes sense for your app).
Works especially well if you're using any kind of hexagonal architecture, make your functional core only accept validated/escaped/parsed/whatever types, and then the imperative shell must send any incoming data through whatever transformation/validation/etc before it can interact with the core.
A license wouldn't stop the unscrupulous people, they'll keep making clones of it and ignoring the license.
This means I have to start chasing any clones, engage legally and try to take them down. It's just not worth the time - I would rather spend the time on improving Monodraw instead.
If unscrupulous people are willing to ignore the license anyway, wouldn't they just hex edit to change the branding to sell clones even while it's closed source?
It seems like an awesome project, I'd say go for it, check /r/ProgrammingLanguages as well. However, typescript is "good enough" for the community, so I don't think it will take off in the sense that you mean.