unless I'm very much mistaken (and I could very well be), that mod is very desirable for a MM, so they can raise the level of thier minions. Of course, it's more desireable on a staff, but it's not that bad on a shield. And by 'ton', I'm speaking figuratively. Obviously it won't fetch what a crystalline or a dwarven axe would.
that's not why I'm wrong, cause the necro can equip the sheild only when creating a minion, to have a chance to raise the level of the minion by 1. otherwise, it's useless. I'm wrong because I thought those mods were very rare and valualbe, when they really aren't.