The use of BSG as filler could allow the valorisation of large amounts of this inexpensive and sustainable by-product of the agri-food industry but in reality, the percentage that can be introduced in polymer matrixes is limited to avoid impairing the thermo-mechanical performances and water resistance. A few examples with successful results were nonetheless listed, requiring improvements with coating or strengthening steps, to fully take advantage of the intrinsic antioxidant and antimicrobial properties of this functional filler. These challenges will need to be addressed and compared to the results of other biomasses to understand better the potential of BSG as natural filler in composite materials.