The services that form a Smart City are nowadays considered in isolation, both in theory and in practice. Moreover, services on different levels of abstraction (key services vs. supportive services) are often depicted side by side without understanding that one is the supportive pillar for one another. This paper identifies the benefits of an integrated view that not only interconnects the services, but also identifies joint layers that they rely on, which helps us to understand the impact of the underlying IT services and the infrastructure they rely on.