They will make a red version eventually I reckon. It might not be as effective, but if I was a soldier I'd be more scared of a huge red glowing beam blowing up tanks than nothing blowing up tanks. It's a moral thing.
(Though, come to think of it, watching a tank explode for no particular reason would freak out the soldiers...)
Gee...I wonder when (if- of course, for now they are probably classified!) we'll see videos of that....? Hey, I pay my taxes - the least these defense contractors can do is to provide some cool vids!
But as to whether IR or visible beams would be more effective on a battlefield, all I know is that the very first days I was on the job at that laser shop, seeing apparently "nothing" cut thru solid steel with only a shower of sparks, could, in certain circumstances, be quite frightening! Seeing something (or someone - ) burst into flame for no apparent reason is the stuff of supernatural horror films....that might work very well in battle IMO.
The new solid state laser for the f-35 is also quite impressive. I remember the prototype was only 15KW, but I also read that with that power it could burn a whole 1 cm in dia but 2 cm deep in steel in only a few seconds!!! The actual production version is going to be 100KW....