Steatotic liver disease (SLD) comprises metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction and alcohol-associated liver disease (MetALD), and alcohol-associated liver disease (ALD), which represent subclasses of liver disorders with overlapping etiologies. MASLD is defined as SLD with cardiometabolic dysfunction, whereas MetALD refers to MASLD with moderate alcohol consumption (140–350 g/week in females and 210–420 g/week in males). Despite being classified as distinct entities, MASLD and MetALD exhibit substantial phenotypic overlap, underscoring the need to delineate their pathological and molecular features and to develop models that capture the synergistic effects of alcohol and metabolic stress. Recent advances in multi-omic technologies have enabled integrated single-cell profiling of genetic, epigenetic, spatial, and proteomic features, providing high-resolution insights into cellular heterogeneity and disease mechanisms. In this review, we examine the pathophysiological landscape of SLD, highlight key distinctions between MASLD and MetALD, and discuss experimental models, including human liver spheroids. These approaches provide deeper insights into disease classification and accelerate the development of targeted therapies.