Structured-light modes have emerged as a promising information carrier for both optical communications and optical computing because they provide high-dimensional spatial degrees of freedom (DOFs) for multiplexing and modal transformation. Although numerous demonstrations have reported increasing transmission capacities and computational functionalities, their practical significance is often evaluated by nominal modal dimensionality rather than system-level usability. In this commentary, we argue that structured-light communications and computing share a common framework of modal transformation and should therefore be assessed using unified system-level criteria. We compare representative structured-light mode groups, discuss their roles in communications and computing, and highlight the practical challenges associated with modal fidelity, modal crosstalk, and scalability. We further propose that the key figure of merit for future structured-light systems should be the usable modal dimensionality achievable under realistic operating conditions, providing a practical perspective for the development of scalable photonic information processing.