Yeah just watched @nealmcspadden video and he did a great job explaining it to me in that video.
And yes if you're doing longer term players then it's not as vital. But changing the keys would require that user trusting your system with even more than the active key which is what I assume is needed for now... but there's really nothing in the account anyway.(Or shouldn't be anything in there)
So yeah that would be cool to have that programmed into it.
As for the reward cards... i feel like the UI you showed made it look like the cards were immediately burned for DEC. BUT... sounds like they're what you're taking as payment for setting up the system?
I own the accounts, so I have all the keys. The user is just delegating to them.
Ottermaker buys the cards for DEC, it doesn't automatically burn them. The system sends the cards out and gets 101% of the burn value in return, which is distributed to the player and owner. Ottermaker then does whatever I feel is appropriate with the cards.