If you were to go for a ride you had to choose between two vehicles. One is a fiberglass vehicle and the other is an aluminum vehicle. The vehicle will be propelled toward a wall at 30 miles per hour. The answer is simple, if you choose to be in the vehicle that shatters upon impact your choice was the glass vehicle.
Fragile aluminum is many times stronger than fiberglass.
If one of your employees accidentally backed your fiberglass vehicle into the protective barrier say at the fuel pump, the area of contact would receive much more structural damage than the aluminum vehicle. The fiberglass would probably be extensively damaged with additional damage continuing beyond the area of impact with structural support requiring repair as well. The repair would require a skilled craftsman in fiberglass repair, a prolonged period of down time and a serious re-inspection by the coast guard. The repair and subsequent down time of a week sends your costs and losses into the stratosphere. Imagine how catastrophic this would be if a similar incident were to happen in the water when you stuck an object in the fiberglass boat.