In the FAA jurisdiction, if an instructor candidate were to become a ground instructor (advanced and instrument) and receive that certificate, then later become a flight instructor (and CFII), would there be any value in retaining the ground instructor certificate? The flight instructor certificates held at that point provide all the same privileges. Is the ground instructor certificate superceded?
The flight instructor certificates held at that point provide all the same privileges.
This is not true. A ground instructor certificate is valid to give ground training for all aircraft... airplane, helicopter, glider, balloon, etc. A flight instructor must have those ratings on their certificate.
Record keeping requirements also differ between the two certificates.
§61.189(b)(2) requires the flight instructor to keep a record of all knowledge test endorsements to include the student name, date, kind of test and result.
The ground instructor has no such requirement.
The flight instructor must also have an advanced or instrument ground instructor certificate to qualify for a gold seal.