Customers often move between websites, mobile applications, social platforms, physical stores, and service desks while completing a single purchase. These movements create opportunities for convenience, but they also expose differences in information, service, and fulfilment. This conceptual review examines how artificial intelligence can support coherent customer experiences across digital and physical touchpoints. It draws on selected peer-reviewed journal articles published from 2020 to 2026 and brings together research on channel integration, AI-enabled marketing, customer experience, and responsible technology use. The review argues that AI contributes to seamlessness when it helps preserve relevant context, improves the reliability of customer promises, and supports useful assistance throughout the journey. Personalisation alone is insufficient. Inaccurate inventory information, disconnected service records, intrusive data collection, and weak human escalation can undermine otherwise advanced systems. A conceptual framework links AI capability and channel integration to customer effort and perceived continuity, with trust, customer control, and human support shaping the resulting experience. Four propositions are offered for future empirical examination. The paper also develops practical implications for journey design, employee coordination, and performance measurement. Its central contribution is to treat seamlessness as a customer judgement about continuity and dependable service rather than as the simple presence of several connected technologies.