What makes quantum technologies tick? Advantages in communication, computation, simulations, metrology and other applications can be traced back to distinct manifestations of quantum theory, such as coherence and entanglement. We characterise these elusive quantum signatures and their operational power under the unifying lens of resource theories. We then show that every (convex) quantum resource yields an advantage in a channel discrimination task, enabling a strictly greater success probability than what is achievable by any state without the given resource. We further discuss recent progress in untapping these benefits for practical quantum-enhanced imaging and sensing tasks.