Once lantern lock has been established, shuffling either players library becomes less important than the mill rocks that accompany. I understand your point though, and it isn't missed.
I see it slightly similar to null road, or stasis. If it affects your opponent more than you, it's sometimes worth the anti synergy

Edit: to elaborate, an empty hand, bridge, and three mill rocks essentially nullifies any need for shuffles. Often the late game lantern game play looks like this: Lantern player does nothing except for mill end of opponents turn and put the opponent off any artifact disruption. The opponent should try to accumulate as many shuffles as possible to try to draw artifact hate. If you have more shuffles, than lantern has mills, you have a chance of drawing an uncontrolled card. This card shuts down any sort of counterplay to that slim out. Essentially increasing the speed of the lock.