The strength of perforated metal is a very important factor when used in stress conditions. This is especially the case when it is used as a protective layer for sound-proofed walls, as well as outdoor barriers or even furniture units.
General speaking, perforated metal is not as strong as non-perforated metal. So it allows designers or engineers to decide what thickness of perforated metal will load the same strength of non-perforated metal. The strongest hole shape and pattern for any given percentage of open area is a 60-degree staggered, round hole pattern.