The main advantage of using agile methodologies in software development is their ability to promote flexibility and adaptability throughout the project lifecycle. Agile allows teams to respond to changing requirements quickly, facilitating iterative development and continuous feedback. This iterative approach leads to frequent releases, enhancing user satisfaction as stakeholders can evaluate and provide input on progress regularly. Additionally, agile encourages collaboration among team members and stakeholders, fostering a shared vision and improved communication, which often results in higher quality products delivered more efficiently.