Fiat Lux

I've pondered what a single civilization that in the vein of China holds to an idea of its continuous existence for 40,000+ years would be like. And in the process of it, I've given it a period when laser swords (as in lightsabers) were predominant. Said civilization used them about 20,000 years ago, and military power marches on in that case. Suppose such a civilization were to re-discover the old laser swords, an entire trove of them in fact....and some dumb fucks decide the best response to modern weaponry is to revert to archaic weapons as a use for terrorism? I could see some extremists using the laser swords again for intimidation purpose (i.e. he/she's badass enough to kill with that old piece of shit? O.o. Run away, run away!), but any large-scale use of them in combat would be the equivalent of the US Army against the Assyrian Army: Curbstomp in favor of plasma rifles and strafing runs that unleash Missile Spam on the laser-sword users.

Though the weapons might be good to intimidate locals who are accustomed to use of Palaeolithic technology and eschew the hypothetical FTL society's regular weapons, and they would also spare expensive assaults with equipment on the equivalent of Aurignacian-era humans. I mean, imagine this:

*Cavemen come running at a laser-sword wielder*

*Laser-sword wielder chops all the cavemen to bits.*

That something is intensely cool to look at would not make it useful. Though dealing with an ancient civilization that discovers weapons like this from its precursors would be interesting as a sci-fi book or summat.