IFF just tells you whether something is friend or foe. NCTR, depending on how good it is, will tell you roughly what it is all the way up to IDing the aircraft specifically
In the Typhoon at the start of a match (especially in a downtier lobby) I’ll use NCTR to pick out weaker targets to lob missiles at from long range (long before their markers), generally produces quite reliable results. Also really nice in SB to know what you have on radar and thus how best to attack or defend against it