Question on copper chimney flashing technique

I recently had new copper flashing installed around chimney due to a leak. A very diligent contractor did the work, which took several hours. The chimney is large (square with each side being 4 feet). I noticed he bent the copper slightly to form a large X design (in the copper) on the front and back of the chimney. The copper goes up about three feet from the roof. His explanation was that it makes the copper more wind resistant and durable (and looks nice). I’ve never seen this before. Would appreciate any comments/thoughts from the experts here on this technique. Thank you

It’s called a cross brake. Makes the metal a little stiffer, used commonly on commercial work here. Big pieces of metal it helps, small stuff i wouldn’t.