Pilot may be expected to use aircraft recognition whilst flying. They need to be able to seperate aircraft apart.
What aircraft recognition was primarily 'invented' for was fighter pilots. They needed to be able to distinguish between friendly and foe. It's no good shooting down the wrong plane!
It is very important air traffic contollers that are able to recognise different aircraft. Imagine being an air traffic controller at Heathrow airport and not knowing a single aircraft?