At the moment you can buy furniture with crowns and then sell it in guild stores or mail it to other players. But I'm also able to sell a stool I've placed in my house (and then removed and taken to the bank), so I don't know if this is intended or not.

It does seem strange to me. Furniture bought with crowns has a little crown icon next to it in the Housing Editor, which seems to indicate they want them to be treated differently, but as far as I can tell they work exactly the same as ones bought with gold.