“You can load up your Card by sending ETH (or Dai) directly to the Card’s address. Deposited ETH will automatically be swapped into Dai in your channel. For now, we enforce a deposit maximum of $30. Any deposits above that amount will be refunded to the sending address(!).”

I seem to be missing something here. The address shown on the card is an Externally owned address (no contract code) so how does ether or Dai get converted?
I received 0.10 via DaiCard but 0.2 Dai sent from Metamask is still sitting in the address and does not show up on the wallet.