The difference is a lot of code that doesn’t exist, some checking of permissions (if you are moving out of a joint pot does the other person know? do they have to approve this somehow?), not to mention the UI itself as we can’t move anything this way so that all needs built from scratch.
If you mean in terms of visibility then I’m guessing because at present it’s a ‘transfer’ there is a clear record of who did what. If I’m just dragging pots around between accounts it might not be as obvious?