This perspective gives an overview of recent progress in the field of photocured polymer composites based on various forms of nanocelluloses, with a focus on cellulose nanofibrils. The manufacturing processes and performances of these nanocellulose composites are detailed, comprising solvent-assisted mixing processes, emulsification, coating and casting processes, preform impregnation, and 3D printing. Attention is also paid to life-cycle engineered approaches to improve their sustainability. These materials find applications in numerous domains, primarily as protective coatings but also as diffusion barrier composites and films for packaging and encapsulation of electronics, as composite hydrogels for biomedical applications, and as membranes for battery technologies.