When you use docker you can have full control over the networking layer already. As you can bound it's networking to another container that will act as proxy/filter. How WASM offer that?

With reverse proxy you can log requests, or filter them if needed, restrict the allowed domains, do packet inspection if you want to go crazy mode.

And if an actor is able to tailor fit a prompt to escape docker, I think you have bigger issues in your supply chain.

I feel this wasm is bad solution. What it brings a VM or docker can't do?

And escaping a docker container is not that simple, require a lot of heavy lifting and not always possible.