Rapid urbanisation and technological developments in the mobility sector underline the importance of the deployment of flexible and complementary public transport services (PTs), such as Demand-Responsive-Transport (DRTs). The deployment of these services is strongly influenced by transport demand; hence it is shaped by socio-economic factors such as booking methods, reasons for travel, and time of travel. Additionally, travel habits and the specific needs of users as well as deployment in areas with low transport demand. This can include not only peripheral regions but also other locations. The integration of DRTs-PTs in Europe and the UK presents a significant opportunity to enhance mobility and sustainability in both urban and rural areas. DRTs have the potential to address the specific transport needs of different regions and contribute to reducing social and gender inequalities while avoiding service bias toward high-demand urban areas. The main goal of this research is to conduct an in-depth analysis of the current state of the art. It focuses on sustainability in the context of DRT mobility, and it also highlights benefits and criticalities through a SWOT analysis approach. This study analyses strengths and weaknesses, opportunities and strategies involved in implementing an integrated DRT-PT service. Ultimately, the findings of this research provide a foundational framework for better deployment of more flexible and complementary PTs, enhancing accessibility and ensuring service equity for all users.