Summary: Take their best card, take something that blanks their plays for a turn or two, or take their one out to your best card
It gets more efficient the more mana you have, which is why it seems to be a better option as a large X spell finisher than most
Using a finger, the player swipes the screen along a predetermined line to, effectively, tear open the cards digital packaging
With Pokemon demand as high as it is, theres a large number of sellers who are flogging fake cards, or are misrepresenting the quality of their stock
But it's possible and looks really neat
User reviews split between people who love the price and people who hit recognition misses on trickier cards, so test it against your own binder before committing your whole collection to it