There's a chance of a decent item in some of those chests, but pretty much it's all random treasure. The gold bullion, IMO, ain't worth it...about like the gemstones.
Be careful when raiding! There's a "slug-in-the-box" in every room, and you don't know which chest it's going to be! Talk about play "button, button, who's got the button!"
-Sazerac