This paper proposes a novel problematique analysis to understand the barriers in adopting blockchain-enabled Internet of Things (IoT) in smart cities. The method integrates the Bayesian best-worst method (BWM) with the Decision-Making Trial and Evaluation Laboratory (DEMATEL) technique and Interpretive Structural Modelling (ISM). The BWM is used to rank barriers based on their perceived urgency from the group of experts, while the integrated DEMATEL-ISM approach provides a structural model to capture the problem complexity, showcasing the interrelationships among the identified barriers through causal diagrams and hierarchical digraphs. This combination allows for a comprehensive metric to rank each barrier, considering both its inherent sense of urgency and its importance from strength of influence over other barriers. A numerical example is presented using a case study in Phnom Penh, Cambodia where the respondents highlight crucial barriers such as the inadequate government policy and regulatory framework on wider adoption of blockchain-IoT solutions as it drives interrelated challenges on scalability, interoperability, and integration of these technologies, and sustainability due to lack of financing and private investments. Through this transparent and systematic approach, policymakers and stakeholders can gain valuable insights to develop effective strategies or interventions for successful adoption of blockchain-based IoT in smart cities in line with Society 5.0 vision.