The real problem with immaterial (now that I thought clearly about it) is that it's enough to chain for 10 turn. You start stalling with your shields circa 10-14 turns and then just play 2 of these fields, will give you 20-24 turns of invincibility. An average rush deck will deck out in 22-23 turns, depending on the coin toss. So without even thinking about 30 turns of chaining, you have 2 of these in your hand after 14 turns (dim shield, lobo, lighting, mindgate, so stalling for 14 turns) and then you play 2 of this card (even increased cost, you will have 20
. And just wait for deckout. I don't know how many decks are at 30 cards, but I think easily the majority of them.
In this case it was just 2 cards, with 3 you can win a game after stalling for 9 turns!! Thats why immaterial is a problem...