The Boerks had a metal helmet inside they did an okay job. The mail coif offers very minimal protection. Anything actauly striking it slaps you in the head, it has no regidity the shock goes straight through into your head. Its use was to stop cuts, a blow to the head would still cause huge amounts of damage.
If we are going to go all, "it doesn't cover the fave its usless" then there are a whole range of helmets that are in the top tier. the Morion for one that offer no protection for the face.
