It's still not JS-level/JS-compatible GC (yet?) and it is still quite low level (more about corralling buffers of bytes than objects, a bit closer to OS-level page management than JS or C# level GC), as it is intended to be lower level than most languages need so that different languages can build different things with it. It is also a tiny stepping stone to better memory sharing with JS APIs (and the eventual goal of WASM "direct DOM"), but still not quite finished on that front as more steps remain.