If they count as armour enough to block spellcasting, then they will (or rather, they must) count as armour enough to block Barbarians and/or monks from using Unarmoured Defence - which would mean your Barbarian with 16/16 would go from 16Ac naked, to 13Ac when wearing those metal gauntlets, because they would not meet the conditions of Unarmoured Defence, and so would have to use the normal AC calculation rules - so 10+Dex Mod, or 13 in this case.
If they aren't doing that, it needs to be reported as a bug, and hopeful Larian will understand that there is a gosh darn reason why all of the magical boot and glove items in the DMG for 5e are soft gloves and simple shoes - not armour.
