Why is the certificate stored on a cryptographic hardware device?
Certificates are stored on cryptographic hardware devices for additional security and as an option to use them from multiple computers.
For AATL Enabled certificates TrustID Business Representative Hardware and TrustID Medium Assurance Unaffiliated Hardware certificates, Adobe®'s technical requirements specify that the issuing Certification Authority must generate them is cryptographic devices with at least FIPS 140-2 Level 2 security. This security feature disable exportation and duplication of the private keys. For this purpose, IdenTrust supports only HID smart cards and HID USB Tokens compliant with the AATL requirement.