If you move, it can't change targets. It's on a cool down. It costs muni. It can be a fairly unreliable ability - there are time s it just collides with something else. Usually craters.
You literally had to stand around for it to do that. I've never wiped a squad with it, because people either move or retreat. Then the damn thing is on cooldown and you can't do anything.
Generally it boils down to this - After you've tried to upgrade your fusiliers you can possibly squeeze in a barrage or two. You can keep doing it but you'll lock yourself out of your doctrinal arty.
So no, the JT isn't a thing that I would consider to use against infantry. Have you ever tried it? It's a pretty terrible ability. It might work if it were a timed damage toggle but if you move out of the barrage area to either charge it or retreat then it's pretty much done because it can't follow up any shots.
Does it matter here? no, JT has AI shells.