The Italian peninsula hosts a vast number of ecclesiastical buildings, many of which were constructed prior to the adoption of modern technical codes. As a result, these structures often lack adequate seismic design, rendering them vulnerable to both global and local damage during seismic events—posing serious threats to architectural heritage and human life. This study aims to evaluate the reliability and effectiveness of the simplified mechanical model proposed in the Italian Guidelines for Cultural Heritage (IGCH) at Evaluation Level 1 (EL1) for the rapid assessment of seismic vulnerability. To this end, a sample of masonry churches located in the municipality of Sorrento (Province of Naples) was selected. Using the CARTIS form, key data regarding the geometry and structural characteristics of each church were collected. Based on data availability and completeness, three churches were chosen for a detailed seismic vulnerability assessment. In the initial phase, the simplified model defined in the IGCH was applied. Subsequently, a more detailed evaluation using the macro-element approach was carried out to examine the global behaviour of the selected churches under seismic loads. Finally, results obtained from the EL1 simplified method were compared with those derived from the more advanced Evaluation Level 3 (EL3), with specific focus on comparing the acceleration factor to the αSLV coefficient. This comparison enabled an assessment of the simplified model’s accuracy in providing rapid damage estimations following seismic events.