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As I understood from the description user can't divide them (it is in the cloakroom!) . There is no small coin feature. Maybe only if you make many smartcards with different nominal value...
I'm not sure it's a good idea. It's better to have one card (NFC) with small coins inside
You have the one SD card with many keys inside (instead of many SD cards with just one key). You can actually see this in the video produced by the creator of this system: http://www.youtube.com/watch?v=ZR8gz0uVBHk&feature=youtu.be
People will naturally tend to add keys for addresses that have balances with sensible denominations such as 100uBTC, 200uBTC, 500uBTC, 1mBTC, 2mBTC, ...., etc, just like regular fiat currency. When you wish to pay someone say for a coffee say of 4700uBTC you give them four 1mBTC coins + one 500uBTC + one 200 uBTC coins (of course eventually the software will automatically do this for you I'd imagine-- its just a knapsack problem algorithm). Also, I imagine that community minded people would set up change vending internet sites or local physical machines where you can exchange your larger coins into smaller or smaller to larger as you require.