Digital Payments and Electronic Commerce in Transition: A Critical Review of Structural Shifts and Integration Pathways

Retail payment systems and electronic commerce have converged over the past decade, yet the scholarly literature describing this convergence remains divided between an economics of payments concerned with instruments, rails and market structure, and a commerce literature concerned with platforms, consumers and firms. This critical narrative review examines what is reliably known about the structural reorganisation of retail digital payments, the parallel reorganisation of electronic commerce around platform intermediaries, and the mechanisms through which the two domains are becoming integrated. Peer-reviewed evidence and authoritative institutional reporting were identified through searches of open scholarly indexes, supplemented by citation tracking and targeted searching of institutional repositories, and appraised for design adequacy, identification strategy, measurement validity and external validity rather than for citation count alone. Four analytical conclusions emerge. First, the shift from card-centred to account-centred architectures is well documented in a small number of large economies, but the causal evidence base is dominated by a handful of natural experiments whose external validity is uncertain. Second, the welfare evidence on electronic commerce is stronger for price and variety effects than for distributional effects, and estimates of consumption gains vary substantially with data source and identification strategy. Third, four integration pathways can be distinguished by evidential status, of which transaction-cost reduction is the best supported and data-driven credit provision the least. Fourth, a large descriptive adoption literature built on intention-based acceptance models contributes little to causal understanding because it measures stated intention rather than realised transaction behaviour. Unresolved questions concern the persistence of competitive gains from publicly operated fast payment systems, the household welfare consequences of credit embedded at the point of sale, and the conditions under which interoperability mandates alter concentration in consumer-facing markets. Confidence in current policy prescriptions is constrained by geographical concentration of the evidence and by the scarcity of long-run follow-up beyond initial adoption episodes.