It has excellent light transmission. It is flame retardant. Tempered glass also has merits. It provides excellent light transmission for plant growth. It is long lasting.
Tempered glass is stronger than regular glass.
However tempered glass may still break during hailstorms and it has a high initial cost. Polyethylene is the least expensive covering material, but it tears and must be replaced every 1-3 years depending on the thickness of the poly used. Acrylic has good light transmission, but it is brittle. A number of materials are effectively used for benching. Extruded metal is commonly used.