Who uses a hardware keylogger?
Parents, for monitoring kids
Employers, for monitoring employee performance
IT administrators, for collecting statistics
Police and investigators, for collecting evidence
Writers, for making a backup of typed text
Shops, stores, and warehouses for keeping track of barcode-scanner data
Law enforcement agencies, for security and forensic purposes
Air traffic management, for storing a history of equipment usage
Postal and delivery services, for forwarding barcode reader data
...and everyone else, for keeping track what's happening on their computer!