Yeah same - use by rookies.
But also, they were not bad in case of a little of help in close-range combat in cramp spaces, like inside UFO, where you really need to hit that guy (not risking missing it). Ofc limited use against hard HP aliens.
EDIT: also good to give rookies/disposable scouts rockets, while rest of team is armored up mostly, so if psi captured they don't do too much damage)?