So is the idea that you would run a normal compiler once in your production pipeline to check syntax, and then re-run it with ts-blank-space to generate the final bundle?

Clearly you can’t eliminate the syntax checking correct?

Yes and the TypeScript ASTs generated while checking the code can be re-used when then running ts-blank-space to generate the JavaScript. Only generating the ASTs once is a significant performance win as this work takes much longer than the type-stripping work.