This paper is endeavored to motivate the use and further research of dissipative and passive discrete-time systems exploiting their frequency-domain characteristics. Some important features and implications of the dissipativity property in the discrete-time setting are collected. These properties are mainly referred to the stability analysis (feedback stability systems and study of the zero dynamics), the relative degree, and the preservation of passivity under feedback and parallel interconnections. Dissipativity frequency-domain properties are related to some of the most important frequency-domain stability criteria.