I expect that bench would be amazingly sturdy. If those bridle joints are tight and glued properly, there's a massive amount of glue surface. Suppose those timbers are 75mm wide (high). Each gluing surface would be 5625mm². Times six faces that's 33,750 mm² of gluing surface area. I've seen catilevered pieces with less gluing surface that were plenty strong. Reitveld's zig-zag chair is a good example.