well, the thing about those missiles is that they are only useful against either weak ships such as shielded fighters and frigates, and are practically useless against anything bigger, really. with the sole exception, of course, of the buffalo II (and freighters) but, well, the buffalo II is the buffalo II. there's not much it
isn't weak against.
Additionally, you need to close the range significantly before engaging, so really, the only ships that are at risk that are larger than a frigate are those that are un-shielded and close to you, and if that's the case, it doesn't really matter what weapon I have on my destroyer, you are not gonna walk away from the fight.
besides, with so little PD and only 1 medium mount, it's effectiveness is very limited to the missiles it can carry, and even a buffalo can take out this missile variant Vraan down once its out of missiles, something that is very possible due to the fact that each missile launcher only has 8 salvos before it runs out (more with the extended missile racks).
edit: welp, did the numbers, six Tviirs will murder
everything smaller than a cruiser, assuming that there is no PDs to intercept, and with the flux generated by the shield so low, you can practically ram your target and then unload everything you have on it point blank, effectively crippling or even overloading their shields without having most of your missiles be shot down on the way.
granted, this requires player intervention, and the AI isn't smart enough to do this trick and even then you will still likely spend most, if not all your missiles in the process, but your point may have merit.