Yes, much faster. Conversely, I don't think Anders is claiming his Typescript implementation to be particularly fast - he believed JS wasn't fast enough to solve his performance problems. Which isn't true.

The TS compiler has always been slow. There are/were several TS-in-Rust/Go compilers long before Anders announced and released the offical Go version. I've also been writing transpilers since before TS was a thing, the TS team could have made it work in JS.

But it's often easier to switch to a language that gives you that structure/performance for free. "Free" in that large companies have the budget to afford a bug-for-bug port/rewrite.