Interesting loophole: It was never stated users had to be creatures
Furrball greetings!
I understand your question, but Zblader made the explained well :
"This card can draw from various aspects of anything That would Represent an ETG you the card," the great majority 99% preferred to use creatures, perhaps because as you thought they only apply to creatures, but it is not only to creature, but yes to card.
And another, the Z, not signaled me about it, but only respect 250 words and link art.
then it is fully legal to use of permanent or spells.