avon1944

Yes it could have value in a close in (guns environment) situation or a "furball". If during a fight the speed of the defensive aircraft falls (around 250Kts) then performing the cobra does have combat value. Doing the cobra 'could' force the offensive aircraft to fly in front of the defensive aircraft. The one real problem is once a pilot uses it, he gives up virtually all his energy. Thus an easy target for some other aircraft.
One Russian test pilot once said, it can have value in deceiving an AEW aircraft. By during the cobra in between radar sweeps, to do the cobra will foil the computer's prediction as to where the aircraft should be in the next sweep.

It does show good stable control at extreme AoA and low speed. It is not something a pilot would do unless in a dire situation.

Adrian