<p>Functional gels exhibit unique properties that can be tuned by regulating their physical interactions and microstructures. However, quantifying the strength and fraction of these physical interactions and how they result in large-scale collective dynamical properties remains a significant challenge. From this perspective, we briefly review the theories and characterization method of light scattering on polyelectrolyte gels, with an emphasis on summarizing our efforts. In particular, we introduce our most recent work on an entirely new universality class of hierarchical gel dynamics for various types of physical gels, which is complementary to the light scattering studies on chemically crosslinked gels in the past five decades. By utilizing the hierarchical gel dynamics, we are able to extract the average bond binding energy of various physical bonds and the physical crosslinking density in the gels. Finally, we evaluated the advantages and limitations of the light scattering method and discussed the future perspectives in this field. It is anticipated that this perspective will facilitate the broad application of light scattering technique in the field of functional gels.</p>