This article synthesizes contemporary research on the multifaceted impacts of piano interaction on human cognition, mental health, and neural processes, and explores its translation into intelligent human-computer systems. Evidence from clinical psychology demonstrates that structured piano training can significantly alleviate anxiety and depression in the elderly, enhance executive functions and working memory in aging populations, and serve as an effective component within multi-element interventions for severe mental illness, as exemplified by the GET UP PIANO trial. Neuroscientific investigations reveal that these benefits are supported by a specialized auditory-motor network, encompassing premotor and parietal cortices, which exhibits significant plasticity in experts and is engaged during both music perception and mental imagery. Unique patterns of musical processing in special populations, such as preserved fronto-temporal connectivity for song in autism spectrum disorder, provide a neurobiological rationale for music-based therapies. Critically, these findings are now informing the development of intelligent technologies. We explore how principles of cross-modal correspondence and personalization are being leveraged to create adaptive systems for health-tech, including closed-loop neurofeedback for neuromodulation, smart keyboards for motor rehabilitation using biofeedback, and AI-driven analysis of musical improvisation for mental health assessment. Finally, the review addresses key challenges, including the need for methodological standardization, mechanistic elucidation, and ethical HCI design focused on data security and long-term engagement. The convergence of neuroscience, clinical practice, and technology positions the piano as a powerful and evolving interface for enhancing human health and cognitive resilience.