Transferring objects from one world to another may not be desirable for a few reasons. This could lead to coupling of world economies where something that is meant to be - intentionally - scarce in one world now finds itself with an overabundance.
there's only one metaverse, and there's only one economy in the metaverse. I'm not advocating that you should be moving game objects between games, that's a distinct concept (and probably not a very useful one). https://news.ycombinator.com/item?id=29086415