Well, that's definitely a sweet-spot, but as a by-product of that, Rust is still a well-thought through language with a strong and logical type system, some very useful features for expressing domain models, etc. and a model of memory management which maps very well to WASM. So if you already know Rust, this is a short and logical step. If you don't already know Rust, I wouldn't learn it just to write web apps in - but if you do, you now have all the advantages of "same language client/server side" as well as the advantages of safety, good libraries in certain spaces, etc.