Yes, you can exchange a paper wallet or coin wallet for goods or services.
You're correct in realizing, though, that the greatest weakness to Bitcoin is its dependency on the network (and more so power/electricity). If the power grid goes down it becomes impossible to access the network upon which most wallets exist and transactions occur.
Maybe unrelated, but this makes me want plugs to put between the wall and all my appliances and gadgets to get a breakdown of my electricity usage.