The purpose is to limit the number of steps in development. If only 50% of users are running the WebAssembly version of a product, and 50% are running the Java

The purpose is to limit the number of steps in development. If only 50% of users are running the WebAssembly version of a product, and 50% are running the JavaScript version of the product, then both need to be stable. Developing in an unrelated language is unlikely to help.