The WASM concept has been around for decades, it's effectively jvm or .net in but in the browser. I don't get the relevance when discussing k8s or containers.
WASM is not just in the browser, which is the key point. But yeah, it is superficially similar to the Java application servers of the past. One big difference is that I can compile, e.g., Rust to WASM but not JVM bytecode. WASM is language agnostic in a way that the JVM isn't. This makes it a good target for shipping apps in a variety of languages that just needs to be scheduled "somewhere", which is the main purpose of a container orchestration platforms like k8s. This is an evolution of serverless, where I won't have to maintain a "cluster" for my compute but just hand off a WASM binary to cloud provider.