It's moot because the product is now dead, but if I understood Coin correctly, all of your criticisms are invalid.

> If you lose it, you have no money unless you have cash on hand or can somehow get money out of the bank

You keep the actual cards at home. So if you lose your Coin, you just go back to your separate cards.

> It is a lot more attractive to thieves / skimmers

The Coin was secured through your phone's passcode/biometrics/pattern, so yeah if they broke that you'd be boned. The same as with GWallet/iPay. A sophisticated mugger could do it I guess.

> if you lose your Coin, that means someone has access to all your cards

Not without the phone.

> you are essentially handing people your entire wallet

No, before you hand it to a waiter or whatever you lock it into the card you want to use.