Unmanaged switches are designed to just plug in and run, with no settings to configure. These are fine to use in small networks with only basic needs. Unmanaged switches are most often seen in very small, uncomplicated networks with only a dozen or so devices connected and without critical requirements for security and availability.
Managed switches, however, are fully configurable, are customizable, and provide a range of data on performance. Those attributes make them more suitable for larger networks and networks supporting critical activities. Typically, such networks power enterprise-level businesses, government agencies, universities, and healthcare organizations.