you're still sacrificing the creatures, meaning you're sacrificing cards, quanta, and attack power to power up a shield that doesn't make you win, and can be destroyed by explosion, etc. Not to mention that momentum will still pass this. In fact, if you were able to put out a ton of creatures to sacrifice, why wouldn't you just go on the offense and win?
And compare this to dissipation field. If that isn't OP when you stock a ton of quanta and have a ton of QTs, then I how would this be OP when sacrificing multiple >20 HP creatures?