To quote the summary of wasmgc feature from Chrome:
> Managed languages do not fit the model of "linear" Wasm with memories residing in one ArrayBuffer. In order to enable such functionality, they need to ship their own runtime which has several drawbacks: (1) it substantially increases binary size of these modules and (2) it's unable to properly deal with links crossing the boundary between the module, other modules and the embedder that all implement their own GC who is not aware of the others.
> WasmGC aims at providing a managed heap that Wasm modules can use to store their own data models while all garbage collection is handled by the embedder.
> Managed languages do not fit the model of "linear" Wasm with memories residing in one ArrayBuffer. In order to enable such functionality, they need to ship their own runtime which has several drawbacks: (1) it substantially increases binary size of these modules and (2) it's unable to properly deal with links crossing the boundary between the module, other modules and the embedder that all implement their own GC who is not aware of the others.
> WasmGC aims at providing a managed heap that Wasm modules can use to store their own data models while all garbage collection is handled by the embedder.