You can't discard nonland cards, even if you want to
High Collectible Value: Japanese Art Rare cards are often sought after by collectors around the world due to their exquisite designs and usually smaller print runs compared to common cards
There is no problem with showing just one card to prove your eligibility, but based on the original work, you have to beat Pegasus to receive the prize money, so you must have both cards
When you have such a deck then Upheaval is one of the most game ending and unrecoverable things that you can be doing, bouncing everything is a lot more brutal when you have no lands left to play the things again with either
What kind of deck do you put it in
For example, the ability of Filigree Attendant applies to determine Phyrexian Ingester's power and toughness, but the ability of Angelic Field Marshal doesn't