It is more attractive because they get to double their gains as MC appreciates against GC.    Say 1 Oz of Gold is worth 100 MC.   Suppose Alice has 100 MC she could create 1 GC by selling it for 100 MC.   You now have an escrow fund with 200 MC (100 from buyer, 100 from seller) that is owned by Alice and 1 GC owned by Bob.    Alice is not allowed to spend the Escrow fund until she buys back the 1 GC.

If GC goes down 50% (MC doubles in value) then Alice can buy back 1 GC for 50 MC and walk away with 150 MC, a profit of 50 MC.  These 50 MC are also worth 2x as much.

As long as the network forces Alice to cover her position before 1 GC is worth 150 MC then Bob has nothing to fear and can be 100% certain the GC will always be worth 1 Gold Coin.