Gnaw to the Bone The most common use for Gnaw to the Bone is in the Pauper format, where you need to stabilize against an aggro/burn deck while youre milling yourself
But that would have included more art, like the backgrounds. Thats basically the same conclusion Id come to when I first looked at these cards
It doesn't copy whether that permanent is tapped or untapped, whether that permanent has any counters on it or any Auras and/or Equipment attached to it, and it doesn't copy any non-copy effects that have changed that permanent's power, toughness, types, color, abilities, or so on
What Barrowgoyf does is add deathtouch , lifelink , and the possibility of snagging a creature from the number of cards it mills off the top of your deck
Still, Im not particularly sure this is worse than Blast of Genius, and I can imagine it being quite a bit better
This six-mana 4/5 is very strong with the card draw, and note it's not ETB, like Soul of the Harvest, but cast