No offense, but what new player is paying 20 gems for a DP chest, instead of waiting for 5 more gems to go for the DF chest? And the only way to collect DP keys is high score on arena and getting to level 60 on the EB, which if you could do that, you wouldn't need the nemesis anyway.
I never noticed this until you mentioned it. I always considered the DP Chest to be super horrible, and majorly outdated. This just further proves how useless DP Keys are. Why waste your gems on the DP Chest, when you could get a DF armor from the other chests.