They protect your unsleeved cards from being scratched up in the deckbuilding phase, and they make it SO much easier to pick up individual cards instead of sliding them to the edge of the table
According to the developers on-stage, they were designed to feel like the " ultimate prize ": according to the team, they look and feel like real gold
Now that there are two Marks writing for the site, I don't know which one to tell you to email
Urban Retreat This is a weird sort of ramp that can also be used to set up some kind of enters trigger, or even make sure something is not on the board when you fire off a wipe
Of course, Tamatoa loves shiny objects
The new ability, Vanish , keeps the Giant Cobra protected from actions , or at least ensures mutal destruction