Yes, the compiled WASM is significantly faster. Easily by an order of magnitude. I might be completely wrong about this but I _think_ if the brilliant folks at Microsoft research in the calc intelligence group would have waited a few years they might have used wasm instead of TypeScript (https://www.microsoft.com/en-us/garage/wall-of-fame/calc-ts-...)

As for Rust, could have been C or Zig. I just needed a language that minimally compiles to wasm.

There is another reason though. IronCalc runs in the bare metal, not only in the web and needs to have bindings to languages like Python, R or Julia. I can't get that today easily with TypeScript.