[SEJeff]

Not necessarily. One of the more dangerous missions of the USAF is SEAD[1]. During Vietnam, the "Wild Weasels"[2] flew these daring missions where the gist was to get all enemy air defense to fire at them, so they could find them, and destroy them. Airborne based anti-missile lasers, such as this, would be utterly devastating for this. It would improve survivability of aircraft flying SEAD missions. SEAD is generally the first step (in US military doctrine) before total domination of the skys. I'd consider that a pretty offensive use of this technology.

[1] https://en.wikipedia.org/wiki/Suppression_of_Enemy_Air_Defen...

[2] https://en.wikipedia.org/wiki/Wild_Weasel

[azernik]

Sure, in the sense that power is generally fungible, these can be offensive. But they don't obsolete the weapons actually used to destroy the targets exposed during that SEADS mission.