Hagen Tank braces

[Aquattro]

If you did the physics on the force applied to the sides of the tank, you'd see that a wimpy little piece of plastic is certainly not holding your tank together. My tank has about 1500 pounds of water in it and uses bracing with snap together corners on the bracing. I can pull these apart by hand, so I'm willing to bet they don't hold my tank together.
The purpose it serves is to make the tank look "finished" and remove the need to polish the edges of the glass. Tank manufacturers put it on to make the tank pretty, and that increases sales.