I'm not sure I understand your point. Typescript is a language with a type checker and compiler. It's the same thing with C. Typescript has to be compiled to run. C has to be compiled to run. When I think of language performance I always default to thinking about runtime performance.
When people talk about C performance, they mean the performance of the code written in C and (ultimately) compiled to machine language. Very seldom they mean the speed of compilation (though they sometimes do, in which case they almost always explicitly mention "compilation").
When people talk about Typescript performance, they either mean Javascript performance or, more likely, the speed with which Typescript type-checks their code; the latter doesn't happen in run time. That's what the original commenter meant when they said "you cannot run Typescript". It's also what TFA means by "performant".
