Plant Molecular Farming (PMF) capitalizes on the unique properties of plants as bioreactors to efficiently produce valuable proteins, pharmaceuticals, and enzymes. This review emphasizes the critical role of transient expression systems, particularly in Nicotiana benthamiana, due to its susceptibility to various pathogens. Viral vector-based transient expression has proven essential during health emergencies like COVID-19, enabling rapid recombinant protein production. The review also evaluates different transient expression platforms and highlights their applications in biopharmaceutical production, education, synthetic biology, and gene editing. Advances in viral vector modification, hydroponics, and Controlled Environment Agriculture (CEA) are presented as transformative innovations enhancing scalability and regulatory compliance. Furthermore, glycoengineering advancements broaden the range of producible biopharmaceuticals, improving global medication access. By exploring these advancements, this review underscores the vast potential of transient expression systems to meet dynamic scientific and market demands, positioning PMF as a vital component in modern biotechnology.