Reduced-order models are widely used to simulate fluid transport in physiological systems, such as airflow in the airways and blood flow in the circulatory system, providing physiological insights at low computational cost. While zero-dimensional (0D) models efficiently capture global system behavior, one-dimensional (1D) models additionally resolve spatial variations and wave-propagation phenomena that are inherently inaccessible to lumped parameter formulations. Although these additional features may offer more detailed physiological information, their practical relevance depends on the specific application, and guidance on when to use which modeling approach remains context-dependent. In current practice, airways are often represented in 0D, whereas blood flow is commonly modeled in 1D. To assess under which conditions 1D formulations offer a meaningful advantage for pulmonary airflow, homogeneous and heterogeneous airway trees are simulated using both 0D and 1D approaches, considering scenarios with compliant and rigid airways. Differences in pressure and flow dynamics are analyzed, especially with respect to the spatial distribution of heterogeneities in diseased lungs. This allows evaluating whether spatio-temporal phenomena that cannot be represented by 0D models are physiologically relevant. The analysis is extended to the pulmonary circulation by comparing fully 1D and fully 0D models, as well as hybrid configurations in which the arterial network is modeled in 1D and the venous network in 0D. The resulting insights aim to clarify when the increased complexity of 1D models is justified by the additional physiological information they provide, and when simpler 0D representations remain sufficient. This supports informed model selection under competing demands of accuracy and computational efficiency and informs subsequent decisions regarding the coupling of airway and pulmonary circulation models.