What's the purpose of paying tributes?

Yesterday late night I found this statue in the desert where I could put a tribute of 2500 gold, if I remember well. I did it but sincerely I didn't understand what's happened. What can I gain paying tributes in this way?

I believe this shrine (or whatever you want to call it) has a chance at giving you an enchanted item. I've only seen one of these, however, so I cannot reliably say that you get something every time.

For me, this shrine appeared while playing as an Engineer. As soon as I paid the tribute, a voice said "You are fortunate" and a rare helmet appeared in the golden cauldron. The helmet was about the same level as my character's current one, but was a welcome piece of loot nonetheless.

There's a nice glowing animation that's played when the item appears in the cauldron; it was especially neat at night-time when my character happened to trigger it.