Java applets needed to interact with the OS in various ways and required browsers to have sub views controlled by plugins. They were a lot more complex and ris

Java applets needed to interact with the OS in various ways and required browsers to have sub views controlled by plugins. They were a lot more complex and risk prone. Especially since Sun kept adding features. WASM is much simpler. It's just a standard bytecode format that the JS engine can handle. It's much easier to secure.