It also needs root access, and 3.10 is only the lowest supported kernel. Not a docker expert but I could bet that they only support a subset of features there.

What I do know is that docker images are specific to the host architecture, supporting either one architecture, or a blessed list. wasm binaries on the other hand aren't. wasm can theoretically also run on bare-metal embedded scenarios without an OS entirely.

But it needs Linux, while wasm runtimes are available for all OSes natively