Well, as I see them, Laser weapons have their uses, at least on MT
At TL8-9, they don't have too high penetration, and they disperse quite quickly (attenuation 2), but see taht in vacuum the attenuation is quite increased, and they have good ranges and are quite useful in zero-g. I guess their uses are mostly for forward observers (where they can use them to mark the tagets for artillery) and in shipboard actions, where you're likely to fight in zero G (gravity plates are TL 10= and against troops armored only by vacc-suits (as they must be protected against vacuum).
At TL13+ they can even be useful against BD, at short ranges, as the laser rifle has pen 20, and their "ammo" is quite high (200 shoots), while keeping their useful in zero-G and their increased attenuation in vacuum.