Swanning around at 15K looking low with PD for the bad guys - because that's what it was best at. However....
Post-USSR inspections of the Backfire/Blackjack revealed no low-level kit. Why not? It seems they tactics were to have been to ingress supersonic at about 50K and loft AS-4/AS-6 under heavy ECM, with the Mx penetrating at 80K+.
So, a "real war machine" in Vietnam, but in Cold War WWIII?
Tomb drivers had a sense of superiority..... Lightning drivers had fun......