Some of us don't like to keep our coins on exchanges as they have a history of being hacked.
It would be cool to be able to track the balance/price of paper wallets and application wallets by address.
Many coins have block websites with public APIs that we can use to fetch the balance by address. For example, Ethereum has: https://etherscan.io/apis#accounts
And bitcoin has: https://blockchain.info/api/blockchain_api
This would be a convenient feature for miners and security conscious HODLers alike.