The efficiency of the lasers go up with the rarity. I had an exotic salvaging laser that had 48% efficiency. If I had a bunch of those I could be stripping wrecks and getting almost half the materials. So yes, that would be useful.
On the other hand, when you have crappy efficiency lasers it might be faster to just destroy the wrecks and take the turrets/upgrades, sell them, and then buy minerals from depots when ever you need them.
Another factor, you can craft turrets. Each Turret depot offers a slightly difference turret configuration. Some offer ones with increased range or efficiency or damage or some combination of 2+. That would probably be a really good way to outfit a bunch of salvaging lasers.