Why do people use GMX email?

Could you elaborate on the reasons why individuals and businesses choose to utilize GMX email? I'm curious to know if it's due to its robust security features, user-friendly interface, or perhaps its integration with other popular platforms. Additionally, I'm interested in understanding if its cost-effectiveness and scalability factor into people's decision-making process. Could you elaborate on these points and provide a concise yet comprehensive overview of the benefits that GMX email offers its users?