I see one use of fighter escort - visual identification and contact with a non-responding aircraft. Happens from time to time.

Late June Gripens of the Hungarian AF intercepted an Emirates A380 overflying the country as it didn't contact with ATC upon entering. Made visual contact with the plane ("yes, a real civilian aircraft, not a Russian bomber") and it's captain ("Thumbs up, we're OK" - "Then contact the bloody ATC!")