Eternity's good for a lot more than just stopping you from decking.
--Immunity to flying weapons other than morning star/glory
--Immunity to PU on your creatures (most of the time)
--Opponent cannot buff creatures
--Removes poison and damage from your creatures
--Blocks one creature ability for one turn
--Card advantage from making your opponent play the same creatures again
--Quantum advantage for the same reason
Definitely one of the stronger weapons if you can fund it. Pulverizer is just stupidly overpowered though because if you enchant it, using an element it already uses, there's only one card in the entire game that can counter it, which you need to draw one of for every single permanent you get, and it requires a specific element to play this card in the first place.