There are two main types of economic benefits that can come from coral reefs. First, there are potential benefits that can come from tourism. Coral reefs can, if they are in good spots in the world, attract many tourists who want to enjoy their beauty. The influx of these tourists can be very beneficial to the economy of the area near which the reef is located. Second, coral reefs can play an important role in important fisheries. In other words, reefs can be important in the life cycles of sea life that can be harvested and sold. Thus, healthy reefs can be economically beneficial both as tourist attractions and as places to harvest sea life.
The main negative impact of coral reefs is connected to the restraints on other economic activity that must be imposed in order to keep the reefs healthy. It is possible that some economic activity onshore would need to be restricted to prevent things like the discharge of harmful materials into the water. These materials could kill the reefs.
Reefs, then, can positively impact economies, but they can also require other economic activities to be curtailed to prevent harm to the reefs.