Wasm is currently an alternative nobody asked for.
What if you want to run your unmodified executable on various architectures?
The JVM kind of does that, but not nearly every language can compile to that as a target, and if you want WASM-like sandboxing you need to deal with security managers, which is no fun at all (and I’ve never seen it done successfully for any non-Java software).
This means that not only do I need to take special care that my code can compile to wasm, but the platform devs (also me, in this case) needs to take special care to support a variety of different design choices in various wasm toolchains.
I’d rather just use SELinux containers and let the OS handle security.
Maybe Firecracker VMs like AWS lambda does.
But for when it's not, I think a platform-independent and language-agnostic bytecode standard is a valuable thing to have.