See your point, Unmissable, but if the ROE lands our intrepid Typhoon pilot within minimum range parameters of AMRAAM/Meteor & ASRAAM, the 'umble 27mm could be handy!
JG's point is apposite. The USN & USAF had effectively decided that the era of the dogfight was over at the time of Vietnam, and then found it wasn't.
Also (and as I'm not a pilot I could well be wrong on this) I thought that having the ability to manoeuvre at highish-g had another use other than air-air combat, namely getting out of the way of a SAM & doing so sharpish!