Use every registered server.
With FREE, only one registered server can be used. If your media is divided between a home NAS, a work server, and an off-site archive, moving between libraries means working around that single-server limit.
PRO unlocks every registered FTP, SFTP, SMB, and WebDAV connection. Each server keeps its own protocol and path, so you can open the library you need without removing or replacing another connection. This is especially useful when photos and videos are intentionally stored across several locations.