What you're describing there sounds more like the Trezor. The OtherCoin is strictly an offline / off-chain payment solution, it is intentionally not capable of signing transactions or dealing with Bitcoin addresses in any way. It just secures a private key and either releases it to the wallet or securely passes it on to another card. The whitepaper at http://www.othercoin.com/OtherCoin.pdf describes it in more detail, it's definitely not a wallet or a way to sign Bitcoin transactions, it has a different purpose.