While it was active, chests, food crates, and some quest items were revealed as a gold dot ( ) on the minimap. If you were on a quest that required gathering specific items scattered around, this skill would track them. For example, the quest In Case of Emergency... asks you to collect 30 pieces of Zeppelin Debris. With Find Treasure on you would be able to see them on your minimap. (Unfortunately, this ability did not seem to reveal anything in Northrend other than chests.)
Patch 7.0.3 (2016-07-19): Re-added as Outlaw Rogue ability.