BPhillipYork: I think the exile/play effect is the real gem here, and I like that there is a payoff for not playing the card, though you have to have some way of using the energy, it's a nice interaction, but at 3 mana a bit pricier than really efficient sources of impulse draw
Whether you grab Darksteel Forge, a key combo piece, or a lock piece, it's an incredibly powerful effect
The Crimson Invasion set contained many of the most popular characters with gorgeous full art cards that captured their personalities perfectly
Right now a vastly inferior Banishing Light is seeing Standard play because 1) some players just don't want to give their opponents Maps, and 2) you do get some positive interaction with Yuna, Hope of Spira and her whole team
Your best bet is to always separate them and only include them if the buylist has a specific category for them
Most error cards can be graded and some errors are even recognized and noted on the graded label
