I have them. I don't think anyone has ever asked about them, let alone commented on them. Most line pilots who were CFI's, that I know, haven't bothered to maintain their CFI. The IGI and AGI don't expire, but I have never met anyone in the last few decades who gave two stuffs about my having them. I seriously doubt they'd make the difference in getting hired anywhere but perhaps an instructing environment.

CFI has this requirement:

§ 61.189 Flight instructor records.

(b) A flight instructor must maintain a record in a logbook or a separate document that contains the following:

(2) The name of each person that instructor has endorsed for a knowledge test or practical test, and the record shall also indicate the kind of test, the date, and the results.

(c) Each flight instructor must retain the records required by this section for at least 3 years.

Ground instructor doesn't. It is one small relief from record keeping.

Back in the Stone Age, either was a requirement for the Gold Seal.
Not so sure if it is still that way these days, too lazy to look it up.

Still a requirement for Gold Seal.