The three main camps of wasm use cases are ( in no particular order )

1. Non browser application (lightweight cloud, plugins, sandboxing)

2. Performance kernels (like compiling a game/rendering engine or AI stuff)

3. Compiling js-like applications from other languages (eg blazor wasm and others)

The only case where DOM access would be useful is 3 and even there 90% of the gains are already available from the JS-strings proposal to avoid copying+reencoding.

Direct DOM access is otherwise mostly a red herring