@tyil this application is actually a combination of 2 ways in which wasm is used. Traditionally it focused on the browser, but recently used also as "edge-based" technology and WASI is part of that.
On the edge means that you can compile the code to run anywhere without having to worry about the infra + architecture. On mobile, IoT, server, browser, cloud, etc.
Here it offers standards-based component-oriented, contract-first (WASI standardizes IDL interfaces), sandboxed, polyglot development.