This shield not only enhances his defense to nigh-invulnerable levels, it also grants him the ability to actually deal decent damage to others by smacking them with it
However, the trade-off is that it grants no other abilities, and is still stuck to his body, so he has to get close enough to somebody to hit them if he wants to use it offensively, and he can only physically block damage, so he has to be facing an attack directly to tank it.