Long-term, I think you’re right. Directed energy weapons that only need electricity (and cooling?) are the way to go. But ABL’s COIL is a step along the way. They’ll develop the tracking and control algorithms, high power optics, characterize how hard you have to hit various targets, etc. The next generation solid-state stuff will benefit from this related work.
What if the bad guys polish the missile to a high reflectivity? Would it matter?