^^^ What he said ^^^
Although you are not required to talk to them, you are much closer to them so they can give you much more relevant information which Farnborough can't. I've not known of any meat bombing there (sky divers) but there's loads of flying training along with the general chaos which that creates. And what about the aircraft that just took off without a transponder, or the aircraft which is doing a practice forced landing from the overhead (joining from above the ATZ)
There are plenty of things which you don't have to do in this game, but it's still a good idea to do them. That's almost the definition of airmanship.