Wasm GC is shipped in stable releases of all major browsers except for Safari but that will be changing shortly if it hasn't already (my info is a few weeks old.) The important thing to note about Wasm is that all important functionality, such as access to I/O and the DOM, have to arrive in the form of host imports to a Wasm module. With this in mind, thanks to Wasm GC it is possible to do web UIs from Wasm by importing the relevant bits of the DOM API that the module needs. Projects like Hoot (Scheme) and Kotlin port are already demoing such things.