The advent of blockchain technology has brought about a sea change in the legal domain, with smart contracts posing a fundamental challenge to traditional contract law. This article analyzes the volatile interface between blockchain smart contracts and legacy legal systems through a comparative, multidisciplinary perspective. Evaluating ten jurisdictions and different blockchain platforms, the study proposes a systematic, computational framework using five indices: The Legal Compatibility Index (LCI), Smart Contract Efficiency Score (SCES), Regulatory Readiness Coefficient (RRC), Fuzzy Composite Literacy Index (FCLI), and Hybrid Arbitration Efficacy Index (HAEI). These indices measure preparedness and success in terms of legal, technical, and institutional capabilities. The results indicate that jurisdictions like Singapore and the USA are leading in legal adoption through preemptive laws, while systems with established statutory rigidity face challenges in enforcing smart contracts. Performance experiments demonstrate high variation in transaction throughput and auditability across blockchain systems. Crucially, hybrid arbitration models, which integrate institutional enforceability with smart contract logic, prove superior for dispute resolution compared to fully decentralized forms. The findings highlight the necessity of coordinated legal reform, stakeholder education, and process innovation to establish blockchain as a legally viable infrastructure. This study presents a rigorous, replicable model to evaluate blockchain adoption in contract law, providing strategic guidance for policymakers, legal scholars, and technologists.