You definitely do not need a DApp interface for a token contract (or any other contract you make on the Ethereum blockchain). DApps just make it easier for users to interact with your contract. Without a DApp, users would have to manually create transactions through their own Ethereum client, which is not impossible to do, but takes more steps. A DApp requires trust though (or a thorough review of the HTML/Javascript code), while manually interacting with a contract yourself does not.
Though you mention a crypto-token for a "normal application"; are you referring to a desktop application? Or a traditional website? If an application does not have any communication to an Ethereum node, it's not able to do anything with the Ethereum network, and wouldn't be able to interact with any crypto-token contracts (its own nor other creators').