Relational Database Management Systems (RDBMS) like SQLite, MySQL, and PostgreSQL are widely used due to their efficient data storage capabilities, and each has distinct characteristics suitable for different applications. SQLite is an embedded, file-based system with a small footprint, ideal for IoT and embedded devices, although it lacks multi-user features and struggles with large datasets. MySQL, favored for its multi-user support and scalability, is optimal for distributed applications and web services but can face performance issues with bulk operations. PostgreSQL, known for its extensibility and standards compliance, excels in analytical applications and offers superior parallel processing but is more resource-intensive and less efficient with frequent updates. Each database has unique advantages and disadvantages, making the choice dependent on specific application requirements, with MySQL being more popular overall, yet PostgreSQL offering robust ACID compliance and SQLite being a lightweight solution for specific use cases.