What reason would there be to conceal runes in your own runedock? Ability: Conceal. Each player has two runes concealed. Ability: Occlude. This unit loses 3 HP and 3 random runes in your runedock are concealed. Would it just be for abilities such as Surge: Concealed? Or are there other reasons?
Also, when runes are concealed they are the first to be revealed next turn. So to a certain extent you can manage your draws (moreso when most runes are concealed).