The crusader meets a chain-mailed opponent one on one. The chain mail is in need of repair, obviously, but unless a well aimed strike just meets a hole, that will not matter much.
You may notice that both shields are somewhat battle damaged, especially at the rim. They are not build to last forever. While you might be able to build such shields, you'd never be able to carry and use them long enough for a battle, especially while wearing plate armor and a none too light sword.