From podcast:
Q: Is there any real use of the Slammer Bottle?
A: Grants some pvpness, some other exciting things. [typing] Actually, that gave me a good idea. [sound of Kinak updating the database] Something really obvious that the broken bottles should have had that they didn't have when they were put in there. Not intended to be the most amazing this, just an easy way to get +pvp or powdered glass.
To do: check what's changed. I'm assuming it can break like the other bottle now.